On automorphic L-functions in positive characteristic

Abstract

We give a proof of the existence of Asai, exterior square, and symmetric square local $L$-functions, $\gamma$-factors and root numbers in characteristic $p$, including the case of $p=2$. Our study is made possible by developing the Langlands-Shahidi method over a global function field in the case of a Siegel Levi subgroup of a split classical group or a quasi-split unitary group. The resulting automorphic $L$-functions are shown to satisfy a rationality property and a functional equation. A uniqueness result of the author and G. Henniart allows us to show that the definitions provided in this article are in accordance with the local Langlands conjecture for ${\mathrm{GL}}_n$. Furthermore, in order to be self contained, we include a treatise of $L$-functions arising from maximal Levi subgroups of general linear groups.

Earlier versions of the paper have an appendix "Uniqueness of Rankin-Selberg products" by G. Henniart and L. A. Lomelí. The appendix was rewritten and is now a separate independent paper

Cited by in corpus (4)

• Galois self-dual cuspidal types and Asai local factors
• Asai cube L-functions and the local Langlands conjecture
• The Langlands-Shahidi method over function fields: Ramanujan Conjecture and Riemann Hypothesis for the unitary groups
• The LS method for the classical groups in positive characteristic and the Riemann Hypothesis