Notice Ulam, Feynman, and von Neumann at Los Alamos in<p><a href="http://www-history.mcs.st-and.ac.uk/BigPictures/Ulam_Feynman_von_Neumann.jpeg" rel="nofollow">http://www-history.mcs.st-and.ac.uk/BigPictures/Ulam_Feynman...</a><p>For the Banach match box problem, that is, flip a fair coin x + y times and find the probability of getting heads exactly x times. So, it's a binomial probability problem.<p>A <i>Banach space</i> is a complete, normed linear space. There is a nice chapter on Banach space in<p>Walter Rudin,
<i>Real and Complex Analysis</i>.<p>There are some nice applications of the Hahn-Banach theorem in<p>David G. Luenberger,
<i>Optimization by Vector Space Methods</i>.<p>In<p>Patrick Billingsley,
<i>Convergence of Probability Measures</i>.<p>is a nice presentation of Ulam's result in measure theory
Le Cam called <i>tightness</i>: Roughly, IIRC, for any probability measure P and any a > 0 no matter how small, there exists a sphere S of finite radius so that P(S) > 1 - a. Intuitively the probability mass can't just keep avoiding all spheres; eventually some sphere, if large enough, must cover nearly all the mass. There are some cute technical details.<p>Once in a paper I used Ulam's result to show that a goofy distribution-free statistical hypothesis test was not trivial. And I've seen other applications.<p>The hypothesis test was to improve on our work in artificial intelligence for zero day monitoring for problems in server farms and networks. So, Ulam's tightness has played a role in at least one piece of work intended to be practical!<p>IIRC, Ulam was long head of Los Alamos. Once I heard his lecture on the role in evolution of having two sexes.<p>There was a Time-Life book on math with a few pages on Ulam. IIRC, Ulam did by hand or mechanical calculator some of the early Monte-Carlo evaluations of critical mass.<p>At<p><a href="http://www.brainyquote.com/quotes/quotes/s/stanislawu312043.html" rel="nofollow">http://www.brainyquote.com/quotes/quotes/s/stanislawu312043....</a><p>is<p>"It is still an unending source of surprise for me how a
few scribbles on a blackboard or on a piece of paper can
change the course of human affairs."<p>Stanislaw Ulam