Characters of twisted fractional linear groups

Averages over classical Lie groups, twisted by characters

We compute EG( ∏ i tr(g λi )), where g ∈G = Sp(2n) or SO(m) (m = 2n, 2n+1) with Haar measure. This was first obtained by Diaconis and Shahshahani [Persi Diaconis, Mehrdad Shahshahani, On the eigenvalues of random matrices, J. Appl. Probab. 31A (1994) 49–62. Studies in applied probability], but our proof is more self-contained and gives a combinatorial description for the answer. We also conside...

Remarks concerning Linear Characters of Reflection Groups

Let G be a finite group generated by unitary reflections in a Hermitian space V , and let ζ be a root of unity. Let E be a subspace of V , maximal with respect to the property of being a ζ-eigenspace of an element of G, and let C be the parabolic subgroup of elements fixing E pointwise. If χ is any linear character of G, we give a condition for the restriction of χ to C to be trivial in terms o...

Twisted signs for p-adic linear groups

Let G be a reductive p-adic group and let θ be an automorphism of G of order at most two. Let π be an irreducible smooth representation of G that is taken to its dual by θ. The space V of π then carries a non-zero bilinear form ( , ) ( unique up to scaling) with the invariance property (π(g)v, π(g)w) = (v, w), for g ∈ G and v, w ∈ V . The form is easily seen to be symmetric or skew-symmetric an...

Twisted Homological Stability for General Linear Groups

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Annals of Mathematics is collaborating with JSTOR to digit...

On the Restriction of Characters of Special Linear Groups of Dimension Three