Jacques Hadamard was one of the great mathematicians of the late 19th and 20th centuries. In addition to his contributions to number theory, differential equations, and mathematical physics, he was also known for his involvement in the Dreyfus Affair, his activism for human rights, and his connections with the founding of the Hebrew University.
Jacques Salomon Hadamard, a renowned French mathematician, was born on December 8, 1865 in Versailles to a Jewish family. In 1867, Jacques moved with his family to Paris. His father was a teacher at the Lyceum, and his mother gave private piano lessons, so Jacques learned to play the violin at an early age. Later, he loved to play with Einstein. Jacques loved to read and was an excellent student at the Lyceum, with honors in a wide variety of subjects, but he did not like arithmetic. However, in the seventh grade, Hadamard had a new mathematics teacher, of whom he said: "[The new teacher] awakened in me the initial, childish feeling of the beauty of scientific truths."
Jacques Hadamard's father loved to study languages, won a competition of scholars in Greek and Latin, loved music and was a lifelong botany enthusiast, even collecting ferns. Jacques Hadamard received his secondary education at the Lycée Louis-Grand. For a certain period he studied at the École Polytechnique, and in 1890 he graduated from the École Normale Supérieure and began teaching. At the age of sixteen he published his first scientific work, and in 1892 he received a doctorate in science.
In 1892, Hadamard married Louise-Anne Ternel, and the couple had three sons and two daughters. His two eldest sons were killed on the fronts of World War I, and his third son was killed in World War II, in 1944. These personal tragedies deeply affected him and turned him into a pacifist.
From 1893 Hadamard worked for a period in Bordeaux, and then in Paris: at the Sorbonne from 1900–1912, at the Collège de France from 1897–1935, at the Ecole Polytechnique from 1912–1935, and at the Central School of Arts and Crafts from 1920–1935. He helped found the Hebrew University of Jerusalem and was an honorary member of its board of trustees. After the death of Henri Poincaré in 1912, Hadamard was elected to fill his place in the French Academy of Sciences.
His main research was devoted to number theory, the theory of analytic functions, differential equations in mathematical physics, and mechanics. He also contributed to group theory. In the theory of differential equations, his research on a difficulty problem for hyperbolic equations was particularly well known. In classical analysis and function theory, Hadamard's inequality and Hadamard's theorem on strong series are well known. He also formulated the concept of "normality" of a problem in mathematical physics, and dealt with the calculus of variations, including the variational formula and Hadamard's theorem. In mechanics, he studied stability problems, properties of trajectories of mechanical systems near an equilibrium state, and problems in gas dynamics. In addition, Hadamard dealt with questions of mathematics teaching in schools and wrote a textbook on geometry.
Hadamard organized a mathematical seminar at the Collège de France, which operated for twenty years. One of his students, Maurice René Percher, recalled: "Thanks to his extensive knowledge and his ability to master every field, Hadamard extended the seminar's activity to all branches of mathematics... Jacques Hadamard continued to listen to lectures even at the age of 90. And how different from his own language the new language of mathematics must have seemed to him! It is difficult to understand even a mathematician fifteen years younger than you. Hadamard had passed before him a series of concepts that did not correspond to the concepts of his youth, but thanks to his knowledge he was able to make connections and understand the essence of the new results and ideas. That is why he was able to ask more questions, and more fundamental questions, than any other listener."
During the German occupation of France from 1940 to 1945, Hadamard was in exile in the United States, where he served as a professor at Yale University. At the end of the war, he returned to France.
Hadamard was interested in the process of formation of mathematical ideas, an interest that was expressed in his famous book "A Psychological Study of the Process of Invention in Mathematics." The book went through many editions. (science.org)
Family relationship to Dreyfus
Hadamard's cousin, Lucie, was the wife of Alfred Dreyfus, and so followed the Dreyfus affair closely. His friend, the mathematician Paul Panelva, who twice served as Prime Minister of France, was initially convinced of Dreyfus's guilt, but under Hadamard's influence began to defend him. Panelva wrote: "Jacques Hadamard, a cousin of Dreyfus's wife, once spoke to me about the 1894 military tribunal. For nearly an hour he tried to convince me of Dreyfus's innocence, and finally, in the face of my incredulity, did everything in his power to make me understand the intrinsic value of his arguments and their absolute lack of appeal. Hadamard told me that he did not know Dreyfus personally at all, that he had seen him only once in his life, that he did not like him, and that his conviction of his innocence was based solely on facts."
Hadamard continued to be involved in human rights activism, taking an active part in the League of Human Rights founded by Émile Zola, opposing nationalist prejudices and supporting the left-wing movements in France of the 1930s, but he did not join any political party. At a ceremony marking the sixtieth anniversary of the League's founding in 1958, he said: "The League continues to exist because it affirms the primacy of moral values, and even today, whenever the law is violated and injustice and arbitrariness prevail, it declares: the Dreyfus affair is not dead!" Having experienced the horror of injustice committed "in the name of state interests", Hadamard opposed anti-Semitism all his life.
Hadamard died in Paris on October 17, 1963, at the age of 97.
High mountain peaks
In 1965, on the centenary of Hadamard's birth, his colleague, the renowned French mathematician Paul Montel, said: "The brilliance of Jacques Hadamard's great mathematical discoveries sometimes dazzles his admirers and prevents them from appreciating his intellectual wealth and moral greatness. He resembles one of those high mountain peaks, which, in order to know well, must be climbed all their slopes. He enjoyed what Anatole France called 'the silent pyramids of the intellect.' He was passionately interested in many works of the human mind and contributed to their realization."
Short questions and answers
Who was Jacques Hadamard?
Jacques Hadamard was an important French mathematician who contributed to number theory, the theory of analytic functions, differential equations, and mathematical physics.
What was Hadamard known for in mathematics?
Hadamard is known, among other things, for his work on number theory, a difficulty problem in differential equations, the concept of the regularity of a mathematical problem, and theorems and inequalities that bear his name.
What was Hadamard's connection to the Dreyfus affair?
Hadamard's cousin, Lucie, was the wife of Alfred Dreyfus. Hadamard was convinced of Dreyfus's innocence on the basis of the facts, and worked to convince others of the injustice done to him.
What was Hadamard's connection to the Hebrew University?
Hadamard helped establish the Hebrew University of Jerusalem and was an honorary member of its board of trustees.
Why is Hadamard also considered a moral and public figure?
Beyond his scientific achievements, Hadamard worked for human rights, opposed anti-Semitism and nationalism, and was active in the League for Human Rights in France.
More of the topic in Hayadan:
6 תגובות
Done. Sorry for the mistakes of the translation machine.
This article needs serious proofreading. At least get the man's name correct. It's Hadamard, not Admer or Edmar.
Thank you for explaining the connection between them
Did you also see Elon Musk's tweet? :-)))
It is written. In the United States
Thanks.
It's always interesting to read you. Where did Hadamard spend World War II?