In mathematics, the Langlands group is a conjectural group LF attached to each local or global field F, that satisfies properties similar to those of the Weil group. It was given that name by Robert Kottwitz. In Kottwitz's formulation, the Langlands group should be an extension of the Weil group by a compact group. When F is local archimedean, LF is the Weil group of F, when F is local non-archimedean, LF is the product of the Weil group of F with SU(2). When F is global, the existence of LF is still conjectural, though Arthur (2002) gives a conjectural description of it. The Langlands correspondence for F is a "natural" correspondence between the irreducible n-dimensional complex representations of LF and, in the local case, the cuspidal automorphic representations of GLn(AF), where AF denotes the adeles of F.
- Kottwitz 1984, §12
- Arthur, James (2002), "A note on the automorphic Langlands group" (PDF), Canad. Math. Bull., 45 (4): 466–482, doi:10.4153/CMB-2002-049-1, MR 1941222
- Kottwitz, Robert (1984), "Stable trace formula: cuspidal tempered terms", Duke Mathematical Journal, 51 (3): 611–650, CiteSeerX 10.1.1.463.719, doi:10.1215/S0012-7094-84-05129-9, MR 0757954
- Langlands, R. P. (1979-06-30), "Automorphic representations, Shimura varieties, and motives. Ein Märchen", Automorphic forms, representations and L-functions, Proc. Sympos. Pure Math., 33, pp. 205–246, ISBN 978-0-8218-1437-6, MR 0546619