Foundations of twisted endoscopy - Introduction

This book develops the foundations of a general theory of twisted endoscopy: definition of endoscopic groups, study of the correspondance between twisted conjugacy classes and conjugacy classes in endoscopic groups, definition of transfer factors, and finally the stabilization of the elliptic part of the twisted trace formula. The book also develops a theory of duality and Tamagawa numbers for the hypercohomology of complexes T --> U of tori.