Representation Theory Ical Atom

Langlands Shahidi method is one of the two main approaches for defining and studying automorphic L-functions. This method is centered around Shahidi local coefficients which are analytic invariants associated with certain induced representations on linear groups. These coefficients arise from a uniqueness result known as uniqueness of Whittaker model. Among the local applications of these coefficients one finds irreducibility results and a formula for Plancherel measures. In the context of metaplectic groups, which are non-linear covering groups, uniqueness of Whittaker model does not hold anymore. Yet, an analog for these coefficients exists, dating back to Kazhdan-Patterson seminal work on the theta representations. In this talk we shall give new and simple interpretation to this analog for coverings of p-adic SL(2) and GL(2) and relate them to Tate gamma factors. We shall also give new formulas for the Plancherel measures and explain how to define gamma factors associated with covering groups using the local coefficients matrix.

We will describe the basic properties of composition algebras, and their classification .

We shall show that the automorphism group of octonion algebra is isomorphism to the simple group of type G2

The celebrated Gan-Gross-Prasad conjectures aim to describe the branching behavior of representations of classical groups, i.e., the decomposition of irreducible representations when restricted to a lower rank subgroup.

These conjectures, whose global/automorphic version bear significance in number theory, have thus far been formulated and resolved for the generic case.

In this talk, I will present a newly formulated rule in the p-adic setting (again conjectured by G-G-P) for restriction of representations in non-generic Arthur packets of GL_n.

Progress towards the proof of the new rule takes the problem into the rapidly developing subject of quantum affine algebras. These techniques use a version of the Schur-Weyl duality for affine Hecke algebras, combined with new combinatorial information on parabolic induction extracted by Lapid-Minguez.