Math 2.0

Number theory Automorphic forms Conjecture

Langlands program

Builds on Galois representationAutomorphic formAdele ringAlgebraic number fieldFrobenius elementPlace (number field)

Statement

The following is the global reciprocity conjecture for GLn\mathrm{GL}_n, one central part of the program. Let FF be an algebraic number field, let GFG_F be its absolute Galois group, let n≥1n \ge 1, and let ℓ\ell be a prime. Fix a field isomorphism ι ⁣:ℚ‾ℓ→ℂ\iota \colon \overline{\Q}_\ell \to \C. Let ρ ⁣:GF→GLn(ℚ‾ℓ)\rho \colon G_F \to \mathrm{GL}_n(\overline{\Q}_\ell) be an irreducible Galois representation. Assume that ρ\rho is unramified at all but finitely many places of FF and de Rham at the places above ℓ\ell. Then there is a cuspidal automorphic representation π\pi of GLn(𝔸F)\mathrm{GL}_n(\mathbb{A}_F), where 𝔸F\mathbb{A}_F is the adele ring of FF, with the following property. For all but finitely many finite places vv of FF, both ρ\rho and πv\pi_v are unramified at vv. Let Frobv\mathrm{Frob}_v be a Frobenius element at vv. Then the Satake parameters of πv\pi_v are, up to the standard normalising twist, the images under ι\iota of the eigenvalues of ρ(Frobv)\rho(\mathrm{Frob}_v).

Remarks

The Langlands program is a web of conjectures proposed by Robert Langlands from 1967 on. It relates Galois representations, automorphic forms and representations of reductive groups over local and global fields. Besides reciprocity, its main parts are the principle of functoriality, which predicts transfers of automorphic representations between different reductive groups, and the local Langlands correspondence. For n=1n = 1, reciprocity is a reformulation of class field theory in terms of Hecke characters. The modularity theorem for elliptic curves over ℚ\Q and Serre's modularity conjecture are proved cases for n=2n = 2 and F=ℚF = \Q. The local Langlands correspondence for GLn\mathrm{GL}_n over a pp-adic field was proved by Harris and Taylor and, independently, by Henniart. In general, both reciprocity and functoriality remain open.

Reading path

To understand this page from the ground up, read these 7 pages in order. The foundations come first.

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Each page uses the pages above it. The colour of the bar on a box shows how strong the evidence is, and the box also gives it as text. The list has the same pages.
  • no evidence level
  1. Adele ring concept
  2. Algebraic number field concept
  3. Automorphic form concept
  4. Frobenius element concept
  5. Galois representation concept
  6. Place (number field) concept
  7. Langlands program conjecture

Further reading

  1. Web https://en.wikipedia.org/wiki/Langlands_program
About this page
TagJ9T2M084W5
URIm2://J9T2M084W5
Kindconjecture
WritingW0 stub
MSC11R39, 11F70, 22E55
StatusThis copy of the site has no build data. Run m2 status J9T2M084W5.
AboutGalois representation, Automorphic form
UsesGalois representation, Automorphic form, Adele ring, Algebraic number field, Frobenius element, Place (number field)
Same as
Changed2 November 2026

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