Pat'sBlog

Friday 19 April 2024

On This Day in Math - April 19

The White Bridge, across from my home in Elk Rapids, Mi.

People must understand that science is inherently neither a potential for good nor for evil. It is a potential to be harnessed by man to do his bidding.
~Glenn T. Seaborg

The 109th day of the year; 109 is a twin prime with 107. I just found out that the product of twin primes (greater than 5) will have a digit root of 8..
5 * 7 = 35, 3 + 5 = 8
11 * 13 = 143, 1 + 4 + 3 = 8
17 * 19 = 323, 3 + 2 + 3 = 8
Hat tip to Ben Vitale

The concatenation of 108 and 109, 108109 is a prime.
107, 108 and 109 can all be formed with some concatenation of the previous or next number.

109 = 1*2+3*4+5*6+7*8+9.

The period of the reciprocal of 109 ends with 853211 (the beginning of the Fibonacci sequence reversed).
0.00917431192660550458715596330275229357798165137614678899082568807339449541284403669724770642201834862385321100917...

109 rotated 180^o is read as 601. I have enlisted the term ambinumerals for such pairs. Numbers like 111 which are the same under rotation are known as strobograms.

EVENTS

1739 John Winthrop (12 Dec 1714-1779) of Cambridge, Mass., the first astronomer of note in the U.S. began sunspot observations and continued over the next two days. No observations were possible on 21 Apr due to cloudy weather. His observations exist as one-page reports in the University Archives of Harvard University, though they were never published. In 1761, he went on an expedition to St. John’s, Newfoundland, to observe the transit of Venus across the sun on 6 Jun 1761, which measurements could be used to compute the distance between the sun and the Earth. He also observed the transit of 1769 from Cambridge.*TIS His great-great-grandfather, also named John Winthrop, was founder of the Massachusetts Bay Colony.

1760 Euler writes the first of many (263) “Letters to a German Princess”.. Madam, The hope of having the honor to communicate, in person, to your Highness, my lessons in geometry, becoming more and more distant, which is a very sensible mortification to me, I feel myself impelled to supply personal instruction by writing, as far as the nature of the objects can permit.” Thus begins the letter on “of maginitude or extension” . the letters will continue, two or more per week, for the next three years. *VFR

1879 “A red letter day in Massachusetts. On that day the second circular which launched the Harvard ‘Annex’, later Radcliﬀe College, was sent out ... ” Mathematics 2 dealt with plane geometry and algebra through quadratics. [Scripta Mathematica, 11(1945), p. 260] *VFR

Responding to calls for equal educational opportunities for women, Harvard President Charles Eliot warned in his 1869 inaugural address that the world “knew next to nothing about the natural mental capacities of the female sex.” In keeping with this belief, he rebuffed attempts to allow women to access a Harvard education. Undeterred, in 1879 a group of reformers founded the Harvard Annex, where women could receive instruction from Harvard faculty. The Annex was soon incorporated as the Society for the Collegiate Instruction of Women under the leadership of Elizabeth Cary Agassiz (1822-1907), the second woman elected to membership in the American Philosophical Society.

A decade later, the Harvard Annex had grown to include more than 200 students and, in 1894, it was chartered as Radcliffe College, with Agassiz as its first president. From the beginning, degrees were countersigned by the Harvard president to attest that they were, in Eliot’s words and despite his reservations, “equivalent in all respects to the degrees given to the graduates of Harvard College.”

Agassiz firmly believed “the College over which she presided was a temporary expedient and that women would soon be admitted as full students to Harvard. She would have more than a century to wait.” *Radcliff History

1957 First FORTRAN program run. The first FORTRAN program (other than internal IBM testing) runs at Westinghouse, producing a missing comma diagnostic. A successful attempt followed.*CHM I think the first actual program run of Fortran is described here. It was a calculation using gamma function. The original FORTRAN programs were prepared on a keypunch machine which punched holes into paper cards which had 80 characters maximum. For this reason, lines in a FORTRAN program are often referred to as "cards." Each card is either a "data" card, a "comment" card or a "statement" card.

Yes, we really did!

1958 France issued a stamp to honor Jean Cavailles (1903–1944) as a hero of the French Underground during World War II. [Scott #879] *VFR He was a French philosopher and mathematician, specialized in philosophy of science. He took part in the French Resistance within the Libération movement and was shot by the Gestapo on February 17, 1944. *Wik

1965 Moore's Law Published: Electronics magazine publishes an article by Gordon Moore, head of research and development for Fairchild Semiconductor and future co-founder of Intel, on the future of semiconductor components. In the article, Moore predicts that transistor density on integrated circuits will double every eighteen months for “at least” the next ten years. This theory will eventually come to be known as Moore’s Law and has largely held true to this day (graph below is up to 2020). Controversy exists over whether Moore’s Law remains applicable, however time will tell just how long Moore’s Law will continue to remain true. *This day in Tech History

1975 India’s ﬁrst scientiﬁc satellite was successfully launched from a Soviet cosmodrome with the help of the Soviet rocket carrier at 1300 hours Indian standard time. The satellite was named Aryabhata, after the famous Indian astronomer and mathematician, who was born in Kusumapura, near present-day Patna, in A.D. 476. [Eves, Return to Mathematical Circles,7◦]*VFR

1977 The German Democratic Republic issued a stamp commemorating the 200th anniversary of Gauss’s birth, 30 April 1777. Besides a portrait of Gauss there is a geometric construction (dealing with the constructible regular polygons?). Why wasn’t it issued on the anniversary day? [Scott #1811] *VFR I found a different stamp than the one Professor Rickey describes issued for the same reason showing complex plane. (pb) also found this anecdote about Gauss recently, "Such was his admiration of Karl Friedrich Gauss that the German mathematician Peter Dirichlet is said to have slept with Gauss's Disquisitiones Arithmeticae under his pillow. [The admiration was mutual: "The total number of Dirichlet's publications is not large," Gauss once remarked. "Jewels are not weighed on a grocery scale." (Gauss's motto? "Few, but ripe.")] *anecdotatge web site and one more note for students.. To understand a little more about "constructible" see this post by Alexander Bogomolny at "Cut the Knot".

1984 In the early 1980's, examination of the fossil record led some archeologists to suggest that there was a pattern of extinctions of species on the earth every 26 million years. On this date, two articles appeared in the same edition of the journal article to explain this. "It is proposed that periodic extinction events are triggered by an unseen companion to the sun traveling in a moderately eccentric orbit which at its closest approach passes through the 'Oort cloud' of comets which surrounds the sun. During each passage this unseen solar companion perturbs the orbits of these comets, sending a large number of them into paths which reach the inner solar system. Several of these hit the earth, on average, in the following million years. At present the unseen companion should be approximately at its maximum distance from the sun, about 2.4 light years, and it will present no danger to the earth until about 15 million years from now." The proposed brown or red dwarf companion to the earth was nicknamed Nemisis, for "Greek goddess of vengeance, personification of divine wrath,". *Nature, *Wik

1988 In an article entitled “Hot hands phenomenon: A myth?” the New York Times (pp. 23, 25) reported on work of the Stanford Psychologist A. Tversky. Most fans believe that a player who has made a string of baskets is likely to succeed on the next try. By examining thousands of shots of the Philadelphia 76ers over a season and a half, Iversky has shown otherwise: Outcomes of successive shots are independent. [Mathematics Magazine 61 (1988), p. 268].*VFR [The article is here (pb)]

BIRTHS

1748 D'Amondans Charles de Tinseau (19 April 1748 in Besançon, France - 21 March 1822 in Montpellier, France) wrote on the theory of surfaces, working out the equation of a tangent plane at a point on a surface, and he generalised Pythagoras's theorem proving that the square of a plane area is equal to the sum of the squares of the projections of the area onto mutually perpendicular planes. He continued Monge's study of curves of double curvature and ruled surfaces, being in a sense Monge's first follower. Taton writes that Tinseau's works, "... deal with topics in the theory of surfaces and curves of double curvature: planes tangent to a surface, contact curves of circumscribed cones or cylinders, various surfaces attached to a space curve, the determination of the osculatory plane at a point of a space curve, problems of quadrature and cubature involving ruler surfaces, the study of properties of certain special ruled surfaces (particularly conoids), and various results in the analytic geometry of space." Two papers were published in 1772 on infinitesimal geometry Solution de quelques problèmes relatifs à la théorie des surfaces courbes et des lignes à double courbure and Sur quelques proptiétés des solides renfermés par des surfaces composées des lignes droites. He also wrote Solution de quelques questions d'astronomie on astronomy but it was never published. He did publish further political writings, as we mentioned above, but other than continuing to correspond with Monge on mathematical topics, he took no further part in mathematics. *SAU

1801 Gustav Theodor Fechner (19 Apr 1801; 18 Nov 1887 at age 86) German physicist and philosopher who was a key figure in the founding of psychophysics, the science concerned with quantitative relations between sensations and the stimuli producing them. He formulated the rule known as Fechner’s law, that, within limits, the intensity of a sensation increases as the logarithm of the stimulus. He also proposed a mathematical expression of the theory concerning the difference between two stimuli, advanced by E. H. Weber. (These are now known to be only approximately true. However, as long as the stimulus is of moderate intensity, then the laws will give us a good estimate.) Under the name “Dr. Mises” he also wrote humorous satire. In philosophy he was an animist, maintaining that life is manifest in all objects of the universe. *TIS

1880 Albert Wallace Hull (19 April 1880 – 22 January 1966) American physicist who independently discovered the powder method of X-ray analysis of crystals (1917), which permits the study of crystalline materials in a finely divided microcrystalline, or powder, state. His first work was on electron tubes, X-ray crystallography, and (during WW II) piezoelectricity. In the 1920's, he studied noise measurements in diodes and triodes. In the 1930's, he also took interest in metallurgy and glass science. His best-known work was done after the war, especially his classic paper on the effect of a uniform magnetic field on the motion of electrons between coaxial cylinders. He also invented the magnetron (1921) and the thyratron (1927), and other electron tubes with wide application as components in electronic circuits.

1880 Evgeny Evgenievich Slutsky (19 April 1880 in Novoe, Yaroslavl guberniya, Russia - 10 March 1948 in Moscow, USSR) Slutsky was important in the application of mathematical methods in economics. Slutsky introduced stochastic concepts of limits, derivatives and integrals between 1925 to 1928 while he worked at the Conjuncture Institute. In 1927 he showed that subjecting a sequence of independent random variables to a sequence of moving averages generated an almost periodic sequence. This work stimulated the creation of stationary stochastic processes. He also studied correlations of related series for a limited number of trials. He obtained conditions for measurability of random functions in 1937. He applied his theories widely, in addition to economics mentioned above he also studied solar activity using data from 500 BC onwards. Other applications were to diverse topics such as the pricing of grain and the study of chromosomes. *SAU

1883 Richard von Mises (19 Apr 1883; 14 Jul 1953 at age 70.) Austrian-American mathematician and aerodynamicist who notably advanced statistics and the theory of probability. Von Mises' contributions range widely, also including fluid mechanics, aerodynamics, and aeronautics. His early work centred on aerodynamics. He investigated turbulence, making fundamental advances in boundary-layer-flow theory and airfoil design. Much of his work involved numerical methods and this led him to develop new techniques in numerical analysis. He introduced a stress tensor which was used in the study of the strength of materials. On Mises' primary work in statistics concerned the theory of measure and applied mathematics. His most famous, yet controversial, work was in probability theory *TIS

1912 Glenn T. Seaborg (19 Apr 1912; - 25 Feb 1999 at age 86) American nuclear chemist. During 1940-58, Seaborg and his colleagues at the University of California, Berkeley, produced nine of the transuranic elements (plutonium to nobelium) by bombarding uranium and other elements with nuclei in a cyclotron. He coined the term actinide for the elements in this series. The work on elements was directly relevant to the WW II effort to develop an atomic bomb. It is said that he was influential in determining the choice of plutonium rather than uranium in the first atomic-bomb experiments. Seaborg and his early collaborator Edwin McMillan shared the 1951 Nobel Prize for chemistry. Seaborg was chairman of the US Atomic Energy Commission 1962-71. Element 106, seaborgium (1974), was named in his honor. *TIS

(Once when being aggressively cross-examined during testimony on nuclear energy for a senate committee, the Senator asked, “How much do you really know about Plutonium.” Seaborg quietly answered, “Sir, I discovered it.” , Which he did as part of the team at the Manhattan Project. *Wik

1966 Brett J. Gladman (April 19, 1966 - ) is a Canadian astronomer and a full professor at the University of British Columbia's Department of Physics and Astronomy in Vancouver, British Columbia. He holds the Canada Research Chair in Planetary Astronomy.
Gladman is best known for his work in dynamical astronomy in the Solar System. He has studied the transport of meteorites between planets, the delivery of meteoroids from the main asteroid belt, and the possibility of the transport of life via this mechanism, known as panspermia. He also studies planet formation, especially the puzzle of how the giant planets came to be.
He is discoverer or co-discoverer of many astronomical bodies in the solar system, asteroids, Kuiper Belt comets, and many moons of the giant planets:

Uranus: Caliban, Sycorax, Prospero, Setebos, Stephano, and Ferdinand
Saturn: A dozen satellites in several groups, each named after a theme of Canadian Inuit gods, French deities, and Norse gods
Neptune: The satellite Neso
Jupiter: Discovery and co-discovery of 6 moons

Gladman is a member of the Canada France Ecliptic Plane Survey (CFEPS), which has detected and tracked the world's largest sample of well-understood Kuiper Belt comets, including unusual objects like Buffy = 2004 XR190 and Drac. *Wik

DEATHS

1567 Michael Stifel (1487 in Esslingen, Germany - 19 April 1567 in Jena, Germany). This number mystic (for his “beasting” of Pope Leo X, see Eves, History,p. 199) became the greatest German algebraist of the sixteenth century. He died on the same date in 1567. [Muller] *VFR His most important work is "Arithmetica integra" (1544) contained important innovations in mathematical notation. It has the first use of multiplication by juxtaposition (with no symbol between the terms) in Europe. He is the first to use the term "exponent". The book contains a table of integers and powers of 2 that some have considered to be an early version of a logarithmic table. In 1532 Stifel published anonymously his "Ein Rechenbuchlin vom EndChrist. Apocalyps in Apocalypsim" (A Book of Arithmetic about the AntiChrist. A Revelation in the Revelation). This predicted that Judgement Day the world would end at 8am on October 19, 1533. When this prediction failed, he did not make any other predictions. *Wik (Some sources say he was also born on April 19)

Stifel was a German monk, Protestant reformer and mathematician. He was an Augustinian who became an early supporter of Martin Luther. He was later appointed professor of mathematics at Jena University.

Here is a clip from Louis Karpinski's Unified Mathematics about Stifel's contribution to logarithms:

1739 Nicholas Saunderson (1 Jan 1682 – 19 April 1739) died of scurvy at age 56. At age 1 he became blind from smallpox. This did not prevent him from learning Greek, Latin and French and “hearing” the works of Euclid, Archimedes, and Diophantus in the original, learning some parts by heart. He created a “palpable arithmetic,” a nailboard for doing arithmetic and forming diagrams with silk threads—the forerunner of the geoboard. He became Lucasian professor at Cambridge in 1711 and earned a reputation as an excellent teacher.*VFR
According to Stephen M. Stigler, he may have been the earliest discoverer of Bayes theorem

J F Ptak posted about his calculator for the blind and I have copied an image of one use of the calculator.

1791 Richard Price (23 February 1723 – 19 April 1791) was a British moral philosopher and preacher in the tradition of English Dissenters, and a political pamphleteer, active in radical, republican, and liberal causes such as the American Revolution. He fostered connections between a large number of people, including writers of the Constitution of the United States. He spent most of his adult life as minister of Newington Green Unitarian Church, where possibly the congregant he most influenced was early feminist Mary Wollstonecraft, who extended his ideas on the egalitarianism inherent in the spirit of the French Revolution to encompass women's rights as well. In addition to his work as a moral and political philosopher, he also wrote on issues of statistics and finance, and was inducted into the Royal Society for these contributions. Price was a friend of the mathematician and clergyman Thomas Bayes. He edited Bayes' most famous work "An Essay towards solving a Problem in the Doctrine of Chances" which contains Bayes' Theorem, one of the most fundamental theorems of probability theory, and arranged for its posthumous publication. Price wrote an introduction to Bayes' paper which provides some of the philosophical basis of Bayesian statistics.
Besides the above-mentioned, Price wrote an Essay on the Population of England (2nd ed., 1780) which directly influenced Thomas Robert Malthus.*Wik

Joseph Priestley, Richard Price and Theophilus Lindsay in the pulpit, in a 1790 engraving satirising the campaign to have the Test Act repealed. The Test Acts were a series of penal laws originating in Restoration England, passed by the Parliament of England, that served as a religious test for public office and imposed various civil disabilities on Catholics and nonconformist Protestants.

1882 Charles Robert Darwin (12 Feb 1809, 19 Apr 1882 at age 73) was an English naturalist who presented facts to support his theory of the mode of evolution whereby favorable variations would survive which he called "Natural Selection" or "Survival of the Fittest," and has become known as Darwinism. His two most important books were On the Origin of Species by Means of Natural Selection (1859) and The Descent of Man, and Selection in Relation to Sex.

1888 Zygmunt Florenty Wróblewski ( 28 October 1845 – 16 April 1888) was a Polish physicist and chemist. He liquefied the “permanent gases” such as nitrogen and carbon monoxide in larger quantities than previously accomplished by Cailletet, whose method he improved. In 1883, he achieved the static liquefaction of oxygen and air. He was the first to liquify hydrogen. Although he achieved it only in a transient fine mist, he published (1885) remarkably accurate data: critical temperature 33 K, critical pressure, 13.3 atm and boiling point, 23 K (modern values 33.3 K, 12.8 atm, 20.3 K). He may also have had a hint of strange electrical properties at very low temperatures, but his research was cut short upon his accidental death. Wroblewski died as a result of burns in a fire started when he overturned a kerosene lamp in his laboratory.*TIS

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1889 Warren De la Rue (15 Jan 1815, 19 Apr 1889 at age 74)English astronomer who pioneered in astronomical photography, the method by which nearly all modern astronomical observations are made. *TIS In 1854 he turned his attention to solar physics, and for the purpose of obtaining a daily photographic representation of the state of the solar surface he devised the photoheliograph, described in his report to the British Association, On Celestial Photography in England (1859), and in his Bakerian Lecture (Phil. Trans. vol. clii. pp. 333–416). Regular work with this instrument, inaugurated at Kew by De la Rue in 1858, was carried on there for fourteen years; and was continued at the Royal Observatory, Greenwich, from 1873 to 1882. The results obtained in. the years 1862–1866 were discussed in two memoirs, entitled Researches on Solar Physics, published by De la Rue, in conjunction with Professor Balfour Stewart and Mr B Loewy, in the Phil. Trans. *Wik

1906 Pierre Curie (15 May 1859, 19 Apr 1906 at age 46)French physical chemist and cowinner of the Nobel Prize for Physics in 1903. His studies of radioactive substances were made together with his wife, Marie Curie, whom he married in 1895. They were achieved under conditions of much hardship - barely adequate laboratory facilities and under the stress of having to do much teaching in order to earn their livelihood. Together, they discovered radium and polonium in their investigation of radioactivity by fractionation of pitchblende (announced in 1898). Later they did much to elucidate the properties of radium and its transformation products. Their work in this era formed the basis for much of the subsequent research in nuclear physics and chemistry. *TIS

1933 Ernest William Hobson FRS (27 October 1856 – 19 April 1933) was an English mathematician, now remembered mostly for his books, some of which broke new ground in their coverage in English of topics from mathematical analysis. He was Sadleirian Professor at the University of Cambridge from 1910 to 1931. He was the brother of the economist John A. Hobson. He became a Fellow of Christ's almost immediately after graduation. He made his way into research mathematics only gradually, becoming an expert in the theory of spherical harmonics. His 1907 work on real analysis was something of a watershed in the British mathematical tradition; and was lauded by G. H. Hardy. It included material on general topology and Fourier series that was topical at the time; and included mistakes that were picked up later (for example by R. L. Moore).*Wik He fought against “the superstition that it is impossible to be ‘rigorous’ without being dull.” “Althouth he lived to be seventy-six he was active almost up to his death; his last book (and perhaps in some ways his best) was published when he was seventy-four. He was a singular exception to the general rule that good mathematicians do their best work when they are young.” See The Mathematical Intelligencer, 6(1984), no. 2, p. 9. *VFR

1914 Charles Sanders Peirce (10 Sep 1839, 19 Apr 1914 at age 74)American scientist, logician, and philosopher who is noted for his work on the logic of relations and on pragmatism as a method of research. He was the first modern experimental psychologist in the Americas, the first metrologist to use a wave-length of light as a unit of measure, the inventor of the quincuncial projection of the sphere, the first known conceiver of the design and theory of an electric switching-circuit computer, and the founder of "the economy of research." He is the only system-building philosopher in the Americas who has been both competent and productive in logic, in mathematics, and in a wide range of sciences. *TIS Charles Sanders Peirce was the son of Sarah Hunt Mills and Benjamin Peirce, himself a professor of astronomy and mathematics at Harvard University, perhaps the first serious research mathematician in America. At 12 years of age, Charles read an older brother's copy of Richard Whately's Elements of Logic, then the leading English-language text on the subject. Thus began his lifelong fascination with logic and reasoning. *Wik

1974 Alexander Dinghas (February 9, 1908 – April 19, 1974) was a Turkish mathematician. He is known for his work in different areas of mathematics including differential equations, functions of a complex variable, functions of several complex variables, measure theory and differential geometry. His most important contribution was his work in function theory, in particular Nevanlinna theory and the growth of subharmonic functions.

Dinghas was not a German and his career during the Nazi years was very difficult. However, after the end of World War II, his luck changed. He became professor of mathematics at the Humboldt University of Berlin in 1947. From 1949 until his death he was a professor of mathematics at the Free University of Berlin and director of the Mathematical Institute there.*Wik

2013 Kenneth Ira Appel (October 8, 1932 – April 19, 2013) was an American mathematician who in 1976, with colleague Wolfgang Haken at the University of Illinois at Urbana-Champaign, solved one of the most famous problems in mathematics, the four-color theorem. They proved that any two-dimensional map, with certain limitations, can be filled in with four colors without any adjacent "countries" sharing the same color. Their conclusion, that four colors would suffice for any map, depended on 1,200 hours of computer time — the equivalent of 50 days — and 10 billion logical decisions all made automatically and out of sight by the innards of an I.B.M. computer at the University of Illinois in Urbana.
He died of esophageal cancer on April 19, 2013. *Wik

As far as is known, the conjecture was first proposed on October 23, 1852, when Francis Guthrie, while trying to color the map of counties of England, noticed that only four different colors were needed. At the time, Guthrie's brother, Frederick, was a student of Augustus De Morgan (the former advisor of Francis) at University College London. Francis inquired with Frederick regarding it, who then took it to De Morgan (Francis Guthrie graduated later in 1852, and later became a professor of mathematics in South Africa).

2016 Walter Kohn (March 9, 1923 – April 19, 2016) Austrian-American physicist who shared (with John A. Pople) the 1998 Nobel Prize in Chemistry. The award recognized their individual work on computations in quantum chemistry. Kohn's share of the prize acknowledged his development of the density-functional theory, which made it possible to apply the complicated mathematics of quantum mechanics to the description and analysis of the chemical bonding between atoms. *TIS
"Paris somehow lends itself to conceptual new ideas. There is a certain magic to that city." (Thanks to Arjen Dijksman)

Credits :
*CHM=Computer History Museum
*FFF=Kane, Famous First Facts
*NSEC= NASA Solar Eclipse Calendar
*RMAT= The Renaissance Mathematicus, Thony Christie
*SAU=St Andrews Univ. Math History
*TIA = Today in Astronomy
*TIS= Today in Science History
*VFR = V Frederick Rickey, USMA
*Wik = Wikipedia
*WM = Women of Mathematics, Grinstein & Campbell

Thursday 18 April 2024

Pandigital Primes

No reason for Wells' book on the cover, I just like the picture. (and his writing)

In mathematics, a pandigital number is an integer that in a given base has among its significant digits each digit used in the base at least once. In base ten such a number might be 123456789098765444321. If the number is prime, which is really cool, it is called a pandigital prime. And if it uses the digits exactly once each, which is even cooler, .... Unfortunately, in base ten, which is where a lot of us hang out the most, you can't have such a number. Any ordering of 1,2,3,4,5,6,7,8,9,and 0 will be divisible by three, and hence - NOT prime. Even if you leave out the zero, you can't make one with the first nine digits either for the same reason.( I know..."Ahhhhh".)(But you can have all of 1 through 9 if the tenth digit is not zero but 1, .... 1234567891 is Prime.)

So there are a couple of ways to adjust. We can look for primes that are n digits long and use the first n numerals, for example 2143 is a four digit prime using the numerals 1,2,3, and 4. The problem with this approach is that there are only two of them. The four digit one is shown, and a seven digit one is 7652413 . Any number made up of the first 2, 3, 5, 6, 8, 9, or ten digits will be divisible by three.

That leaves a couple of options. I got started thinking about these when I wrote a blog awhile back called "The Game of Primes ." The object was to create a string of primes by starting with one prime number and then adding a digit each time to make the string a longer prime, but using any of the ten decimal numerals as a digit. So you could start with 2, then add 3 to get 23, etc. I only got to seven, you may be able to do better. There is a nine digit prime (several of them) that has no repeated numerals. I found 576849103 is prime and so is 987654103. Having pretty much reached the ends of my manual calculating limits, I asked on twitter, "Is there a nine digit prime using distinct digits that includes a two?"
Faster than a nano-bullet I got a response from ‏ @n0m0 who advised me that "First nine digit prime with distinct digits that includes number 2 is 102345689, second is 102345697 and so on again!"

Realizing I had a computation wizard on the line (at least relative to me) I wondered aloud, (or Atweet)

"Is it possible to form an eleven digit Pandigital Prime (ie repeating only one of the 0-9)" Again at something akin to the speed of light, he responded with two examples; "First pandigital prime with 11 digits is 10123457689, next one is 10123465789 and so on..."

Then, realizing he had a rube on line whose non-programming nose could easily be pushed in the mud, he sent me a list of several... you can count them, and lock this away if you are looking for 11-digit primes...

Here is the first few, but the whole list he has graciously placed here. List of 11 digit pandigital primes filtered from ~10 million primes

10123457689
10123465789
10123465897
10123485679
10123485769
10123496857
10123547869
10123548679
10123568947
10123578649
10123586947
10123598467
10123654789
10123684759
10123685749
10123694857
10123746859
10123784569
10123846597
10123849657
10123854679
10123876549
10123945687
10123956487
10123965847
10123984657
10124356789
10124358697
10124365879
10124365987

On This Day in Math - April 18

It is nothing short of a miracle that modern methods of instruction have not yet entirely strangled the holy curiosity of inquiry.
~Albert Einstein

The 108th day of the year; 108 can be written as the sum of a cube and a square (a^3 + b^2) in two ways. This is the smallest number with this property. *Prime Curios

AND 108 = 1¹ • 2² • 3³ *jim wilder ‏@wilderlab

The concatenation of 108 with its previous and next number is prime, i.e., 108107 and 108109 are primes.

108 is the smallest possible sum for a set of six distinct primes such that the sum of any five is prime: {5, 7, 11, 19, 29, 37}. (Don't just sit there, there must be another that is larger. Find it.

Today and tomorrow are both examples of ambinumerals, numbers which form a different number when rotated 180^o 108 becomes 801. Numerals like 181 which stay the same when rotated are called strobogrammatic numerals

EVENTS

1557 Maurolico completed the ﬁrst volume of his Arithmetic at three o’clock in the morning on Easter Sunday. [Jean Cassinet, Mathematics from Manuscript to Print, 1300–1600, p. 162; Thanks to Dave Kullman]*VFR Throughout his lifetime, he made contributions to the fields of geometry, optics, conics, mechanics, music, and astronomy. He edited the works of classical authors including Archimedes, Apollonius, Autolycus, Theodosius and Serenus. He also composed his own unique treatises on mathematics and mathematical science.

His Arithmeticorum libri duo (1575) includes the first known proof by mathematical induction. (Yea!)

His De Sphaera Liber Unus (1575) contains a fierce attack against Copernicus' heliocentrism, in which Maurolico writes that Copernicus "deserved a whip or a scourge rather than a refutation". (Boo!)

His unpublished manuscript Compaginationes solidorum regularium (1537) includes a statement of Euler's formula V-E + F = 2 for the Platonic solids, long before Leonhard Euler formulated it more generally for convex polyhedra in 1752.

Maurolico's astronomical observations include a sighting of the supernova that appeared in Cassiopeia in 1572. Tycho Brahe published details of his observations in 1574; the supernova is now known as Tycho's Supernova. *Wik

Star map of the constellation Cassiopeia showing the position (labelled I) of the supernova of 1572; from Tycho Brahe's De nova stella

1694 An ad for William Leybourne's Pleasure with Profit appears in The Proceedings of the Old Bailey:

Pleasure with Profit: Consisting of Recreations of divers kinds, viz. Numerical, Geometrical, Mathematical, Astronomical, Arithmetical, Cryptographical, Magnetical, Authentical, Chymical, and Historical. Published to Recreate Ingenious Spirit, and to induce them to make further scrutiny how these (and the like) Sublime Sciences. And to divert them from following such Vices, to which Youth (in this Age) are so much inclin'd. By William Laybourn, Philomathes.

A nice discussion of the "Uphill Climber", one of the problems in the book, is explained by the excellent mathematical writer, Julian Havel. *http://plus.maths.org

1775 Paul Revere’s Ride. The revolutionary War began the next day. Now you probably think this has nothing to do with mathematics, but how do you suppose he got that lantern up in the church steeple? Easy, he used a key to get in. Since he was a change ringer, a highly mathematical activity, he needed a key to get up to the bells. *VFR
Revere was not in the church himself that night, and two families claim credit for their ancestor being the actual hanger of the lights. A plaque in the Old North Church (by his ancestors) credits Robert Newman, a Sexton of the church who probably had a key himself. (Maybe less math than we thought) And don't be fooled by the SEXton to think it is related to six, it is from the same root as sacred. PB

1796 Professor E. A. W. Zimmerman sends a short notice of Gauss’s work on constructibility of regular polygons (see March 30, 1796) to the Jenenser Intelligenzblatt. He adds, “It is worthy of notice that Herr Gauss is now in his 18th year and has devoted himself here in Brunswick to philosophy and classical literature with just as great success as to higher mathematics.” [Tietze, 204] *VFR (found this on Twitter from Matt Henderson....and loved it..
"Erdős believed God had a book of all perfect mathematical proofs.
God believes Gauss has such a book.")

1810 Gauss elected a member of the Berlin Academy of Sciences. *VFR

1831 Founding of the University of the City of New York. [Muller] *VFR

1831, Sophie Germain wrote a letter to her friend Libri which describes Galois' situation.

"... the death of M. Fourier, have been too much for this student Galois who, in spite of his impertinence, showed signs of a clever disposition. All this has done so much that he has been expelled form École Normale. He is without money ... They say he will go completely mad. I fear this is true."

Galois then took Cauchy's advice and submitted a new article On the condition that an equation be soluble by radicals in February 1830. The paper was sent to Fourier, the secretary of the Paris Academy, to be considered for the Grand Prize in mathematics. Fourier died in April 1830 and Galois' paper was never subsequently found and so never considered for the prize.

By 31 May, Galois was dead.

1853 Ana Roqué de Duprey (Aguadilla, Puerto Rico, April 18, 1853 - Río Piedras ,Puerto Rico October 5, 1933) was a writer , educator , activist for women's rights and one of the founders of the University of Puerto Rich . In addition, she is considered one of the precursors of feminism in Puerto Rico , and founded the Puerto Rican Women's League in 1917 , the first organization attached to this movement in that country.

Her mother died when she was only four years old and she was raised by her father, her aunt, and her grandmother, all of whom were educators. In 1860, when she was seven years old, she was sent to a regular school, and two years later she graduated. She left school and dedicated herself to sewing with her grandmother, Ana María Tapia de Roque, who had also been a teacher, and continuing arithmetic with her father. She continued her education at home and in 1864, at the age of eleven, she became the youngest teaching assistant in Puerto Rico. In 1866, at age thirteen, she founded a school in her home. She also wrote a student text on geography , which was later adopted by the Puerto Rico Department of Education. She applied for her teaching license and passed the exams.

In 1884, she was offered a position as a teacher in Arecibo which she accepted. Additionally, she enrolled in the Provincial Institute where she studied philosophy and science , and she obtained her bachelor's degree . In 1894 she founded the magazine La Mujer , which became the first publication to have a Puerto Rican woman as editor.

She was also the founder of La Evolución (1902), La Mujer del Siglo XX (1907), Album Puertorriqueño (1918) and Heraldo de la Mujer (1920). In 1899, she was appointed director of the San Juan Normal School.

She was passionate about astronomy ; she would be named an honorary member of the Society of Astronomers of France.

Roqué was, along with Isabel Andreu de Aguilar (1887-1948) and Mercedes Sola (1879-1923), a renowned feminist activist. In 1917, she founded the Liga Femínea de Puerto Rico, the first organization of its kind in that country that was dedicated to issues related to women's rights ; Some of their assemblies were held in San Juan , Ponce , and Arecibo , and one of their first actions was to send a request for women's suffrage to the legislature. In 1924, she founded the Puerto Rican Association of Women Suffragettes, which became one of the most powerful organizations in her fight to establish women's right to vote, a task that became a reality in 1932 and entered into force for all women in 1935.

1881, The Natural History Museum in London @NHM_London was opened for the public. It is one of the largest natural history museum‘s of the world.* @SCIHIBLOG

1905 The first mention of the word genetics seems to occur in a letter from William Bateson to Adam Sedgwick.

First page of a 1905 letter written by William Bateson, first Director of the John Innes Institute, to Adam Sedgewick, Cambridge professor. The transcription of the letter is the following: 'Dear Sedgewick, if the Quick fund were used for the foundation of a Professorship relating to Heredity and Variation the best title would I think, be 'The quick professorship of the study of heredity.' No single word in common use quite gives this meaning. Such a word is badly wanted, and if it were desirable to coin one, 'Genetics' might do. Either expression clearly …' Published with permission from the Bateson estate. Courtesy of the Cambridge University Library.

1942 GE builds first US Jet Aircraft Engine: In1941, the U.S. Army Air Corps picked GE's Lynn, Massachusetts, plant to build a jet engine based on the design of Britain's Sir Frank Whittle. Six months later, on April 18, 1942, GE engineers successfully ran the I-A engine.
In October 1942, at Muroc Dry Lake, California, (today, Edwards Air Force Base) two I-A engines powered the historic first flight of a Bell XP-59A Airacomet aircraft, launching the United States into the Jet Age. *About GE website

Bell P-59B Airacomet

1958 On his 100th birthday India issued a stamp commemorating the centenary of the birth of Dr. Dhondo Keshav Karve (1858–1922), pioneer of women’s education. [Scott #299]*VFR

Popularly known as Maharshi Karve, he was a social reformer in India in the field of women's welfare. He advocated widow remarriage and he himself married a widow. Karve was a pioneer in promoting widows' education. He founded the first women's university in India - SNDT Women's University .The Government of India awarded him with the highest civilian award, the Bharat Ratna, in 1958, the year of his 100th birthday.He organized a conference against the practice of devdasi. He started 'Anath balikashram' an orphanage for girls. His intention was to give education to all women and make them stand on their own feet. Through his efforts, the first women university was set up in 20th century.

The appellation Maharshi, which the Indian public often assigned to Karve, means "a great sage".

1986 IBM First to Use Megabit Chip:
Newspapers report that IBM had become the first computer manufacturer to use a megabit chip -- a memory chip capable of storing 1 million bits of information -- in a commercial product, its Model 3090. The announcement is heralded as a notable triumph for American computer makers, whose work had been perceived as having fallen behind that of the Japanese electronics industry.*CHM

'This is a signal of our semiconductor technology leadership,'' said Jack D. Kuehler, the I.B.M. senior vice president who heads all of the company's manufacturing operations. And the chip itself, he quickly added, comes not from a fabrication laboratory in a Tokyo suburb, but from I.B.M.'s own semiconductor operations in Essex Junction, Vt.

But industry analysts say the victory may be more symbolic than substantive. Dozens of American manufacturers have fled the commodity memory chip business, unable to match Japan's remarkable manufacturing efficiencies or constant price cutting. Japan Has 85% of the Market

IBM 3090

2011 Scientists demonstrate mathematically that asymmetrical materials should be possible; such material would allow most light or sound waves through in one direction, while preventing them from doing so in the opposite direction; such materials would allow the construction of true one-way mirrors, soundproof rooms, or even quantum computers that use light to perform calculations. *Wik

BIRTHS

1772 David Ricardo (18 April 1772 – 11 September 1823) was an English political economist, often credited with systematizing economics, and was one of the most influential of the classical economists, along with Thomas Malthus, Adam Smith, and John Stuart Mill. He was also a member of Parliament, businessman, financier and speculator, who amassed a considerable personal fortune. Perhaps his most important contribution was the law of comparative advantage, a fundamental argument in favor of free trade among countries and of specialization among individuals. Ricardo argued that there is mutual benefit from trade (or exchange) even if one party (e.g. resource-rich country, highly skilled artisan) is more productive in every possible area than its trading counterpart (e.g. resource-poor country, unskilled laborer), as long as each concentrates on the activities where it has a relative productivity advantage. *Wik

1838 Paul Émile Lecoq de Boisbaudran (18 April 1838 – 28 May 1912) French chemist who developed improved spectroscopic methods which had recently been developed by Kirchhoff. In 1859, he set out to scan minerals for unknown spectral lines. Fifteen years of persistence paid off when he discovered the elements gallium (1875), samarium (1880), and dysprosium (1886). He ranks with Robert Bunsen, Gustav Kirchhoff and William Crookes as one of the founders of the science of spectroscopy. Guided by the general arrangement of spectral lines for elements in the same family, he believed the element he called gallium (in honour of France) was the eka-aluminium predicted by Mendeleev between aluminium and indium. Since it is liquid between about 30 - 1700 deg C, a gallium in quartz thermometer can measure high temperatures. *TIS

1863 H(ugh) L(ongbourne) Callendar (18 Apr 1863, 21 Jan 1930) was an English physicist famous for work in calorimetry, thermometry and especially, the thermodynamic properties of steam. He published the first steam tables (1915). In 1886, he invented the platinum resistance thermometer using the electrical resistivity of platinum, enabling the precise measurement of temperatures. He also invented the electrical continuous-flow calorimeter, the compensated air thermometer (1891), a radio balance (1910) and a rolling-chart thermometer (1897) that enabled long-duration collection of climatic temperature data. His son, Guy S. Callendar linked climatic change with increases in carbon dioxide (CO2) resulting from mankind's burning of carbon fuels (1938), known as the Callendar effect, part of the greenhouse effect.*TIS

Callendar received awards such as the James Watt Medal of the Institution of Civil Engineers (1898) and the Rumford Medal (1906).[3] He was elected as a Fellow of the Royal Society, and later a member of the Physical Society of London. Callendar was also nominated for the Nobel Prize in Physics three times. *Wik

llustration of calorimeter by H.L. Callendar:

1892 Dmitrii Evgenevich Menshov (18 April 1892 in Moscow, Russia - 25 Nov 1988)
For his work on the representation of functions by trigonometric series, Menshov was awarded a State Prize in 1951. He was then elected a Corresponding Member of the USSR Academy of Sciences in 1953. In 1958 Menshov attended the International Congress of Mathematicians in Edinburgh and he was invited to address the Congress with his paper On the convergence of trigonometric series. *SAU

1907 Lars Valerian Ahlfors (18 Apr 1907; 11 Oct 1996 at age 89) Finnish mathematician who was awarded one of the first two Fields Medals in 1936 for his work with Riemann surfaces. He also won the Wolf Prize in 1981.*TIS

He is remembered for his work in the field of Riemann surfaces and his textbook on complex analysis. His book Complex Analysis (1953) is the classic text on the subject and is almost certainly referenced in any more recent text which makes heavy use of complex analysis. Ahlfors wrote several other significant books, including Riemann surfaces (1960)[5] and Conformal invariants (1973).

1904 Stefan E Warschawski (18 April 1904 in Lida, Russia (now Belarus)- 5 May 1989 in San Diego, California, USA) With careful scholarship, he made lasting contributions to the theory of complex analysis, particularly to the theory of conformal mappings. With keen judgment, he guided two mathematics departments to eminence. With modest gratitude, he cemented many friendships along the way.*SAU

He wasa professor and department chair at the University of Minnesota and the founder of the mathematics department at the University of California, San Diego.

After receiving his Ph.D., Warschawski took a position at Göttingen in 1930 but, due to the rise of Hitler and his own Jewish ancestry, he soon moved to Utrecht University in Utrecht, Netherlands and then Columbia University in New York City.[1]

After a sequence of temporary positions, he found a permanent faculty position at Washington University in St. Louis in 1939. During World War II he moved to Brown University and then the University of Minnesota, where he remained until his 1963 move to San Diego, where he was the founding chair of the mathematics department. Warschawski stepped down as chair in 1967, and retired in 1971, but remained active in research: approximately one third of his research publications were written after his retirement. Over the course of his career, he advised 19 Ph.D. students, all but one at either Minnesota or San Diego. Vernor Vinge is among Warschawski's doctoral students.

1911 Maurice Goldhaber (18 Apr 1911; 11 May 2011 at age 100) Austrian-American physicist who devised an experiment to show that neutrinos always rotate in one direction (only counterclockwise). His method was simple, elegant, and used an apparatus small enough to fit on a benchtop, rather than employing a huge accelerator. He also discovered that the nucleus of the deuterium atom consists of a proton and a neutron. In the decade (1961-73) that he headed the Brookhaven National Laboratory in New York, he oversaw the experiments there which led to three Nobel Prizes. He died at age 100.*TIS

In 1934, working at the Cavendish Laboratory in Cambridge, England he and James Chadwick, through what they called the nuclear photo-electric effect, established that the neutron has a great enough mass over the proton to decay.

He moved to the University of Illinois in 1938. In the 1940s with his wife Gertrude Scharff-Goldhaber he established that beta particles are identical to electrons.

1916 Ellis Robert Kolchin (April 18, 1916 – October 30, 1991) was an American mathematician at Columbia University. Kolchin earned a doctorate in mathematics from Columbia University in 1941 under supervision of Joseph Ritt. He was awarded a Guggenheim Fellowship in 1954 and 1961.
Kolchin worked on differential algebra and its relation to differential equations, and founded the modern theory of linear algebraic groups.*Wik

1918 Hsien Chung Wang (18 April 1918 in Peking (now Beijing), China - 25 June 1978 in New York, USA)worked on algebraic topology and discovered the 'Wang sequence', an exact sequence involving homology groups associated with fibre bundles over spheres. These discoveries were made while he worked with Newman in Manchester. Wang also solved, at that time, an important open problem in determining the closed subgroups of maximal rank in a compact Lie group. *SAU

1928 Mikio Sato (April 18, 1928 - ) is a Japanese mathematician, who started the field of algebraic analysis. He studied at the University of Tokyo, and then did graduate study in physics as a student of Shin'ichiro Tomonaga. From 1970 Sato has been professor at the Research Institute for Mathematical Sciences, of Kyoto University.
He is known for his innovative work in a number of fields, such as prehomogeneous vector spaces and Bernstein–Sato polynomials; and particularly for his hyperfunction theory. This initially appeared as an extension of the ideas of distribution theory; it was soon connected to the local cohomology theory of Grothendieck, for which it was an independent origin, and to expression in terms of sheaf theory. It led further to the theory of microfunctions, interest in microlocal aspects of linear partial differential equations and Fourier theory such as wave fronts, and ultimately to the current developments in D-module theory. Part of that is the modern theory of holonomic systems: PDEs over-determined to the point of having finite-dimensional spaces of solutions.
He also contributed basic work to non-linear soliton theory, with the use of Grassmannians of infinite dimension. In number theory he is known for the Sato–Tate conjecture on L-functions.*Wik

1945 Joseph Bernstein (April 18, 1945, ) is an Israeli mathematician working at Tel Aviv University. He works in algebraic geometry, representation theory, and number theory.
Bernstein received his Ph.D. in 1972 under Israel Gelfand at Moscow State University. He was a visiting scholar at the Institute for Advanced Study in 1985-86 and again in 1997-98.
Bernstein was elected to the Israel Academy of Sciences and Humanities in 2002 and was elected to the United States National Academy of Sciences in 2004. In 2004, Bernstein was awarded the Israel Prize for mathematics. In 2012 he became a fellow of the American Mathematical Society. *Wik

1949 Charles Louis Fefferman ( April 18, 1949, )born in Washington, D.C. In 1978 he received a Fields Medal for his work on complex analysis.*VFR As a child prodigy, his accelerated schooling resulted a B.S. degrees in physics and mathematics by age 17 and a Ph.D. in mathematics at age 20 from Princeton University (1969). When in he became a professor (1971) at the University of Chicago at the age of 22, he was the youngest full professor ever in the U.S. Two years later, he returned to Princeton as a professor (1973). His Ph.D. dissertation was on "Inequalities for Strongly Regular Convolution Operators." His field of study includes his interest in physics - applied mathematics in vibrations, heat, turbulence, though he is best known for his theoretical work. *TIS

He was a child prodigy entered the University of Maryland at age 14,[3][4][7] and had written his first scientific paper by the age of 15. He graduated with degrees in math and physics at 17, and earned his PhD in mathematics three years later from Princeton University, under Elias Stein. His doctoral dissertation was titled "Inequalities for strongly singular convolution operators". *WIK

DEATHS

1756 Jacques Cassini (18 Feb 1677; 18 Apr, (or Sometimes given 16 Apr) 1756 at age 79) French astronomer whose direct measurement of the proper motions of the stars (1738) disproved the ancient belief in the unchanging sphere of the stars. He also studied the moons of Jupiter and Saturn and the structure of Saturn's rings. His two major treatises on these subject appeared in 1740: Elements of Astronomy and Astronomical Tables of the Sun, Moon, Planets, Fixed Stars, and Satellites of Jupiter and Saturn. He also wrote about electricity, barometers, the recoil of firearms, and mirrors. He was the son of astronomer, mathematician and engineer Giovanni Cassini (1625-1712) with whom he made numerous geodesic observations. Eventually, he took over his father's duties as head of the Paris Observatory.*TIS Cassini was born at the Paris Observatory and died at Thury, near Clermont. Admitted at the age of seventeen to membership of the French Academy of Sciences, he was elected in 1696 a fellow of the Royal Society of London, and became maître des comptes in 1706. *Wik

1674 John Graunt- (24 Apr 1620, 18 Apr 1674 at age 54) English statistician, generally considered to be the founder of the science of demography, the statistical study of human populations. His analysis of the vital statistics of the London populace influenced the pioneer demographic work of his friend Sir William Petty and, even more importantly, that of Edmond Halley, the astronomer royal. *TIS
John Graunt was the first person to compile data that showed an excess of male births over female births. He also noticed spatial and temporal variation in the sex ratio, but the variation in his data is not significant. John Arbuthnott was the first person to demonstrate that the excess of male births is statistically significant. He erroneously concluded that there is less variation in the sex ratio than would occur by chance, and asserted without a basis that the sex ratio would be uniform over all time and space. (pb)

1802 Erasmus Darwin (12 December 1731 – 18 April 1802) Prominent English physician, poet , philosopher, botanist, naturalist and the grandfather of naturalist Charles Darwin and the biologist Francis Galton. Erasmus Darwin was one of the leading intellectuals of 18th century England. As a naturalist, he formulated one of the first formal theories on evolution in Zoonomia, or, The Laws of Organic Life (1794-1796). Although he did not come up with natural selection, he did discuss ideas that his grandson elaborated on sixty years later, such as how life evolved from a single common ancestor, forming "one living filament". Although some of his ideas on how evolution might occur are quite close to those of Lamarck, Erasmus Darwin also talked about how competition and sexual selection could cause changes in species.. *TIS

Among many other inventions, all of which he chose not to patent, were a horizontal windmill, which he designed for Josiah Wedgwood (who would be Charles Darwin's other grandfather), a carriage that would not tip over (1766), a steering mechanism for his carriage, known today as the Ackermann linkage, that would be adopted by cars 130 years later (1759), and a method for lifting and lowering barges on canals.

The last he propose two water-filled boxes that would work as counterweights for each other as barges were lifted up or down between levels.

The Lunar Men is a wonderful book about Erasmus, hs period and his wide range of friends and contacts.

1803 Louis François Antoine Arbogast (October 4, 1759 – April 8, or April 18, 1803) His contributions to mathematics show him as a philosophical thinker somewhat ahead of his time. As well as introducing discontinuous functions, he conceived the calculus as operational symbols. The formal algebraic manipulation of series investigated by Lagrange and Laplace in the 1770s was put in the form of operator equalities by Arbogast in 1800 in Calcul des dérivations.*SAU

1883 Édouard Albert Roche (17 Oct 1820, 18 Apr 1883 at age 62) was a French mathematical astronomer who studied the internal structure of celestial bodies and was the first to propose a model of the Earth with a solid core. He determined (1850) the Roche Limit for a satellite to have a stable orbit around a planet of equal density. The smaller body could not lie within 2.44 radii of the larger body without breaking apart from effect of the gravitational force between them. He later made a rigorous mathematical analysis of Pierre Laplace's nebular hypothesis and showed (1873) the instability of a rapidly rotating lens-shaped body.*TIS

1913 Mary Cannell (19 July 1913 in Liverpool, England - 18 April 2000) It was the work which she undertook after she retired which earns her a place as a highly respected historian of mathematics. Her work stemmed from the fact that George Green had worked as a miller near Nottingham. Green was a mathematician who was well known to almost all students of mathematics around the world, yet little was known of his life. Flauvel writes:- ... widespread knowledge of Green himself dates only from the 1970s when Cannell and other Nottingham colleagues worked to restore his windmill and his memory...When I first visited Green's windmill in Nottingham the booklet which I purchased was George Green Miller and Mathematician written in 1988 by Mary Cannell. She produced a major biography of Green, George Green : Mathematician and Physicist 1793-1841 : The Background to His Life and Work in 1993. In addition she wrote research articles on Green's life and work bringing to the world of mathematics an understanding of Green's remarkable life.
Flauvel writes:- She charmed audiences on several continents, promoting interest in Green and early 19th-century mathematical physics, in the clear tones and pure vowels of pre-war English, somewhere between Miss Marple and Dame Peggy Ashcroft. ... Mary Cannell was working on projects of one sort or another - the Green website, the revised edition of the biography, research papers, the catalogue in the university of Nottingham library - right to the end, in days filled with her characteristic energy and enthusiasm. *SAU

1923 Pieter Hendrik Schoute (January 21, 1846, Wormerveer–April 18, 1923, Groningen) was a Dutch mathematician known for his work on regular polytopes and Euclidean geometry. *Wik Schoute was a typical geometer. In his early work he investigated quadrics, algebraic curves, complexes, and congruences in the spirit of nineteenth-century projective, metrical, and enumerative geometry. Schläfli's work of the 1850's was brought to the Netherlands by Schoute who, in three papers beginning in 1893 and in his elegant two-volume textbook on many-dimensional geometry 'Mehrdimensionale Geometrie' (2 volumes 1902, 1905), studied the sections and projections of regular polytopes and compound polyhedra. ... Alicia Boole Stott (1870-1940), George Boole's third daughter (of five), ... studied sections of four- and higher-dimensional polytopes after her husband showed her Schoute's 1893 paper, and Schoute later (in his last papers) gave an analytic treatment of her constructions. *SAU

1945 Sir John Ambrose Fleming (29 Nov 1849, 18 Apr 1945 at age 95)English engineer who made numerous contributions to electronics, photometry, electric measurements, and wireless telegraphy. In 1904, he discovered the one directional current effect between a positively biassed electrode, which he called the anode, and the heated filament in an evacuated glass tube; the electrons flowed from filament to anode only. Fleming called the device a diode because it contained two electrodes, the anode and the heated filament. He noted that when an alternating current was applied, only the positive halves of the waves were passed - that is, the wave was rectified (from a.c. to d.c.). It would also take a radio frequency wave and produce d.c.corresponding to the on and off of the Morse code transmitted signals. *TIS Fleming called his invention a “thermionic valve.”

1955 Albert Einstein (14 Mar 1879; 18 Apr 1955 at age 76) German-American physicist who developed the special and general theories of relativity and won the Nobel Prize for Physics in 1921 for his explanation of the photoelectric effect. Recognized in his own time as one of the most creative intellects in human history, in the first 15 years of the 20th century Einstein advanced a series of theories that proposed entirely new ways of thinking about space, time, and gravitation. His theories of relativity and gravitation were a profound advance over the old Newtonian physics and revolutionized scientific and philosophic inquiry.*TIS
An NBC News broadcast of his death is here.

1991 Sir Austin Bradford Hill CBE (8 July 1897 – 18 April 1991) was an English epidemiologist who pioneered the modern randomised clinical trial and, together with Richard Doll, demonstrated the connection between cigarette smoking and lung cancer. Hill is widely known for pioneering the "Bradford Hill" criteria for determining a causal association.

In 1922, Hill went to work for the Industry Fatigue Research Board. He was associated with the medical statistician Major Greenwood and, to improve his statistical knowledge, Hill attended lectures by Karl Pearson. When Greenwood accepted a chair at the newly formed London School of Hygiene and Tropical Medicine, Hill moved with him, becoming Reader in Epidemiology and Vital Statistics in 1933 and Professor of Medical Statistics in 1947.

Hill had a distinguished career in research and teaching and as author of a very successful textbook, Principles of Medical Statistics, but he is famous for two landmark studies. He was the statistician on the Medical Research Council Streptomycin in Tuberculosis Trials Committee and their study evaluating the use of streptomycin in treating tuberculosis,[6] is generally accepted as the first modern randomised clinical trial. The use of randomisation in agricultural experiments had been pioneered by Ronald Aylmer Fisher. The second study was rather a series of studies with Richard Doll on smoking and lung cancer. The first paper, published in 1950, was a case-control study comparing lung cancer patients with matched controls. Doll and Hill also started a long-term prospective study of smoking and health. This was an investigation of the smoking habits and health of 40,701 British doctors for several years (British doctors study).

On Hill's death in 1991, Peter Armitage wrote, "to anyone involved in medical statistics, epidemiology or public health, Bradford Hill was quite simply the world's leading medical statistician."

1999 Gian-Carlo Rota Rota (April 27, 1932 – April 18, 1999) worked on functional analysis for his doctorate and, up to about 1960, he wrote a series of papers on operator theory. Two papers in 1959-60, although still in the area of operator theory, looked at ergodic theory which is an area which requires considerable combinatorial skills. These papers seem to have led Rota away from operator theory and into the area of combinatorics. His first major work on combinatorics, which was to change the direction of the whole subject, was On the Foundations of Combinatorial Theory which Rota published in 1964.

Rota received the Steele Prize from the American Mathematical Society in 1988. The Prize citation singles out the 1964 paper On the Foundations of Combinatorial Theory as:-... the single paper most responsible for the revolution that incorporated combinatorics into the mainstream of modern mathematics. *SAU

2003 Edgar Frank Codd (19 August 1923 – 18 April 2003) -American computer scientist and mathematician who laid the theoretical foundation for relational databases, for storing and retrieving information in computer records. He also contributed knowledge in the area of cellular automata. *TIS

Edgar Frank Codd studied mathematics and chemistry at Exeter College, Oxford, before serving as a pilot in the RAF Coastal Command during the Second World War, flying Sunderlands. In 1948, he moved to New York to work for IBM as a mathematical programmer.[9] Codd first worked for the company's Selective Sequence Electronic (SSEC) project and was later involved in the development of IBM 701 and 702.

In 1953, dismayed by Senator Joseph McCarthy, Codd moved to Ottawa, Ontario, Canada. In 1957, he returned to the US working for IBM and from 1961 to 1965 pursuing his doctorate in computer science at the University of Michigan in Ann Arbor. Two years later, he moved to San Jose, California, to work at IBM's San Jose Research Laboratory, where he continued to work until the 1980s. He was appointed IBM Fellow in 1976. During the 1990s, his health deteriorated and he ceased work.

Codd received the Turing Award in 1981, and in 1994 he was inducted as a Fellow of the Association for Computing Machinery. *Wik