Bernard Morris Dwork, “Bernie” to those who had the privilege of knowing him, died on May 9, 1998, just weeks short of his seventyfifth birthday. He is survived by his wife of fifty years, Shirley; his three children, Andrew, Deborah, and Cynthia; his four granddaughters; his brothers Julius and Leo; and his sister, Elaine Chanley. We mention family early in this article, both because it was such a fundamental anchor of Bernie’s life and because so many of his mathematical associates found… Expand

When I first met Alexander Grothendieck more than fifty years ago I was not only deeply impressed by his creativity, his knowledge and many other aspects of his mathematics, but I also wondered where… Expand

Grothendieck visited Pisa twice, in 1966, and in 1969. It is on these occasions that he conceived his theory of crystalline cohomology and wrote foundations for the theory of deformations of… Expand

We give an exposition of Dwork's construction of Frobenius structures associated to generalized hypergeometric equations via the interpretation of the latter due to Gelfand-Kapranov-Zelevinsky in the… Expand

We describe an algorithm for computing, for all primes $p \leq X$, the mod-$p$ reduction of the trace of Frobenius at $p$ of a fixed hypergeometric motive in time quasilinear in $X$. This combines… Expand