Langlands base change for GL(2)

THE JACQUET-LANGLANDS CORRESPONDENCE FOR GL2 Contents

1.1. Matching regular semisimple conjugacy classes. Let X(F ) = F × F×, viewed as the space of semisimple conjugacy classes in GL2(F ) via GL2(F ) → X(F ) sending γ 7→ (Tr(γ),det(γ)). Similarly we have D× → X(F ) sending γ′ 7→ (TrD/F (γ),NmD/F (γ′)), where TrD/F and NmD/F mean reduced trace and norm. For regular semisimple γ ∈ GL2(F ) and γ′ ∈ D×, we write γ ∼ γ′ if they have the same image in ...

Base Change for Semiorthogonal Decompositions

Let X be an algebraic variety over a base scheme S and φ : T → S a faithful base change. Given an admissible subcategory A in D(X), the bounded derived category of coherent sheaves on X, we construct an admissible subcategory AT in D b(X×ST ), called the base change of A, in such a way that the following base change theorem holds: if a semiorthogonal decomposition of D(X) is given then the base...

Non - Abelian Base Change For

Prerequisites for the Langlands Program∗

For learning about the Langlands program, knowledge of Lie-group structure theory, algebraic number theory, algebraic geometry, modular forms, and infinite-dimensional representation theory is appropriate. This article describes how one can get a glimpse of the program with less background than this.

Base Belief Change for finitary monotonic logics

We slightly improve on characterization results already in the literature for base revision. We show that in order to axiomatically characterize revision operators in a logic the only conditions this logic is required to satisfy are: finitarity and monotonicity. A characterization of limiting cases of revision operators, full meet and maxichoice, is also offered. In the second part of the paper...