Everett stayed in Madison throughout the war. Later he joined me at Los Alamos, where we did much more work together including our now well-known collaboration and work on the H-bomb.
Everett exhibited a trait of mind whose effects are, so to speak, non-additive: persistence in thinking. Thinking continuously or almost continuously for an hour, is at least for me — and I think for many mathematicians — more effective than doing it in two half-hour periods. It is like climbing a slippery slope. If one stops, one tends to slide back. Both Everett and Erdös have this characteristic of long-distance stamina.
There were also Donald Hyers and Dorothy Bernstein. Hyers also had persistence in thinking about problems and an ability to continue to push the train of thought on a specific problem; we wrote several joint papers together. Dorothy Bernstein was a graduate student in my class. She was an interested, enthusiastic, and faithful taker of notes and organizer of material from a course I taught on measure theory. She collected much material, and we intended to write a book together, but our work was interrupted by my departure from Madison in 1944 and our plans were abandoned.
One day in my office, a young and brilliant graduate student named Richard Bellman appeared and expressed a desire to work with me. We discussed not only mathematics but the methodology of science. When the United States entered the war, he wanted to go back East — I believe to New York where he came from — and asked me to help him obtain a fellowship or a stipend so he could continue working after he left Madison. I remembered that in Princeton Lefschetz had some new scientifico-technological enterprise connected with the war effort. I wrote to him about Bellman in a sort of Machiavellian way, saying that I had a very able student who was so good that he deserved considerable financial support. I added that I doubted that Princeton could afford it. This, of course, immediately challenged Lefschetz and he offered Bellman a position. Two years later, Dick Bellman appeared suddenly in Los Alamos in uniform as a member of the SEDs, a special engineering detachment of bright and scientifically talented draftees who had been assigned to help with the technical work.
Through my connections with physicists and a seminar I taught in physics in the absence of Gregory Breit, I heard of the recent arrival in Madison of a very famous French physicist, Léon Brillouin. I called on him and found that his wife, Stéfa, was Polish, born in the city of Lódz, a large textile-manufacturing town. Stéfa and Léon had met when she was a young student in Paris, and they were married sometime before World War I. When World War II broke out he was, I think, a director of the French broadcasting service, with all the military responsibilities that entailed. After the collapse of France and the installation of the Vichy régime, he managed to escape from France at the first opportunity. He was internationally known for his work in quantum theory, statistical mechanics, and also in solid state physics. In fact, he was one of the pioneers in the theory of solid state. (The idea of "Brillouin" zones and other important notions are due to him.) He was also a very prolific and successful writer of physics textbooks and monographs.
Mrs. Brillouin had a great artistic flair. In the early nineteen-twenties she acquired, for modest sums, many works by Modigliani, Utrillo, Vlaminck, and other painters. In Madison she herself started to paint flower compositions in oil made tip of thick layers — a style all her own. The Brillouins invited us to stop at their apartment the day Françoise and I were married. They held a small surprise reception for us, where we drank French champagne and partook of a memorable cake by Stéfa. Stéfa Brillouin spoke hardly any English, but a few weeks after her arrival, in shopping for various objects she discovered that "le centimètre d'ici" as she called our inch, was about two and a half times the "centimètre de France." This almost exact estimate, the inch being 2.54 centimeters, was obtained solely by looking at the sizes of materials, curtains, and rugs. In Madison a close association began, which continued long after the war and lasted until their deaths a few years ago.
Before my second year in Madison, I was promoted to an assistant professorship — a step which gave me hope and some confidence in the material aspects of the future. To start a home and at the same time help support my brother on my modest salary (of twenty-six hundred dollars a year) was difficult. Often to make ends meet I visited the Faculty Credit Union, where a sympathetic officer made me loans of up to one hundred dollars, which had to be repaid in a few months' time.
I was asked to run the mathematics colloquium, which took place every two weeks and involved both local and visiting mathematicians. I might add that the payments to speakers were ridiculously small; even for those times, they amounted to about twenty-five dollars — and this included traveling expenses.
The colloquium was run differently from what I had known in Poland, where speakers gave ten- or twenty-minute informal talks. At Madison they were one-hour lectures. There is quite a difference between short seminar talks like those at our math society in Lwów, and the type of lecture which necessitates talking about major efforts. The latter were better prepared, of course, but their greater formality removed some of the spontaneity and stimulation of the shorter exchanges. In this connection I met André Weil, the talented French mathematician, who had gone to South America at the beginning of the war. He disliked conditions there and came to the United States, where he had gotten a job at Lehigh. Weil was already well known internationally for his important work in algebraic geometry and in general algebra. His colloquitim talk was on one of his most important results on the Rieman hypothesis for fields of finite characteristic. The Rieman hypothesis is a statement that is not easy to explain to laymen. It is important because of its numerous applications in number theory. It has challenged many of the greatest mathematicians for about a hundred years. It is still unproved although considerable progress has been made toward a possible solution.
Dean Montgomery, a friend I had met at Harvard, came at my invitation and gave a colloquium talk. There was a vacancy in the department, and I tried to interest him in coming to our university, where Ingraham and Langer, the two most senior professors, were both very much in favor of his appointment; instead he went to Yale. Later he told me stories about the atmosphere at Yale, which at that time in some circles was ultra-conservative. In his interview he was asked whether he was for or against Jews in the academic profession and also whether he was a liberal. Even though he answered both questions "wrongly" front the interlocutor's point of view, he nevertheless received an offer. He left Yale a few years later to join the Institute in Princeton.
Eilenberg and Erdös were also among the speakers invited to the colloquia. Erdös was one of the few mathematicians younger than I at that stage of my life. He had been a true child prodigy, publishing his first results at the age of eighteen in number theory and in combinatorial analysis.
Being Jewish he had to leave Hungary, and as it turned out, this saved his life. In 1941 he was twenty-seven years old, homesick, unhappy, and constantly worried about the fate of his mother who had remained in Hungary.
His visit to Madison became the beginning of our long, intense — albeit intermittent — friendship. Being hard-up financially—"poor," as he used to say — he tended to extend his visits to the limits of welcome. By 1943, he had a fellowship at Purdue and was no longer entirely penniless—"even out of debts," as he called it. During this visit and a subsequent one, we did an enormous amount of work together — our mathematical discussions being interrupted only by reading newspapers and listening to radio accounts of the war or political analyses. Before going to Purdue, he was at the Institute in Princeton for more than a year with only a pittance for support that was to end later.