Japan. J. Math. 10, 237--248 (2015)

From Pierre Deligne's secret garden: looking back at some of his letters

L. Illusie

Abstract: I discuss four unpublished letters of Deligne (one on Hodge theory, two on Euler--Poincaré characteristics and ramification of $\ell$-adic sheaves, one on generalized divisors), and sketch some of the developments they generated.