Ngô Bao Châu recently won a Fields Medal for his work on the Fundamental Lemma, conjectured by Langlands many years ago. But the relationship between the result proved by him and Langlands’ original conjecture might not be so clear to someone who has not followed the development closely. The original idea involvedwhat Langlands calls endoscopy—to explain harmonic analysis on reductive groups ov...

Functoriality conjecture is one of the central and influential subjects of the present day mathematics. Functoriality is the profound lifting problem formulated by Robert Langlands in the late 1960s in order to establish nonabelian class field theory. In this expository article, I describe the Langlands-Shahidi method, the local and global Langlands conjectures and the converse theorems which a...

In this paper, we present a refinement of the global Langlands correspondence for discrete symplectic motives of rank 2n over Q. To such a motive Langlands conjecturally associates a generic, automorphic representation π of the split orthogonal group SO2n+1 over Q, which appears with multiplicity one in the cuspidal spectrum. Using the local theory of generic representations of odd orthogonal g...

In the late 1960s, Robert Langlands proposed a new and far-reaching connection between the representation theory of Lie groups over real and -adic fields, and the structure of the Galois groups of these fields [24]. Even though this local Langlands correspondence remains largely conjectural, the relation that it predicts between representation theory and number theory has profoundly changed our...

The transfer factors for standard endoscopy involve, among other things, the Langlands-Shelstad splitting invariant. This note introduces a twisted version of that splitting invariant. The twisted splitting invariant is then used to define a better twisted factor ∆I . In addition we correct a sign error in the definition of twisted transfers. There are two ways to correct the sign error. One wa...

We show that the numerical local Langlands duality for GLn and the T-duality of twodimensional quantum gravity arise from one and the same symmetry principle. The unifying theme is that the local Fourier transform in both its `-adic and complex incarnation gives rise to symmetries of arithmetic and geometric local Langlands parameters.

We explain, in the case of good reduction, the conjecture of Langlands and Rapoport describing the structure of the points on the reduction of a Shimura variety (Langlands and Rapoport 1987, 5.e, p169), and we derive from it the formula conjectured in (Kottwitz 1990, 3.1), which expresses a certain trace as a sum of products of (twisted) orbital integrals. Also we introduce the notion of an int...

When I was asked to suggest a Bulletin article worthy of reprinting, I knew the answer right away: An Elementary Introduction to the Langlands Program by Steven Gelbart, published by the Bulletin in 1984, remains one of the best reviews of the Langlands Program, even though this subject has expanded tremendously in the intervening years. This paper has greatly influenced my own research and is ...

Let G = Sp(2n,C) be a complex symplectic group. We introduce a G× (C)-variety Nl, which we call the l-exotic nilpotent cone. Then, we realize the Hecke algebra H of type C (1) n with three parameters via equivariant algebraic K-theory in terms of the geometry of N2. This enables us to establish a Deligne-Langlands type classification of simple H-modules under a mild assumption on parameters. As...

It has been common wisdom among mathematicians that Extended Topological Field Theory in dimensions higher than two is naturally formulated in terms of n-categories with n > 1. Recently the physical meaning of these higher categorical structures has been recognized and concrete examples of Extended TFTs have been constructed. Some of these examples, like the Rozansky-Witten model, are of geomet...