English

Character Varieties of Abelian Groups

Representation Theory 2015-05-27 v4 Algebraic Geometry

Abstract

We prove that for every reductive group G with a maximal torus T and the Weyl group W there is a natural normalization map chi from T^N/W to an irreducible component of the G-character variety of Z^N. We prove that chi is an isomorphism for all classical groups. Additionally, we prove that even though there are no irreducible representations in the above mentioned irreducible component of the character variety for non-abelian G, the tangent spaces to it coincide with H^1(Z^N, Ad rho). Consequently, this irreducible component has the "Goldman" symplectic form for N=2, for which the combinatorial formulas for Goldman bracket hold.

Keywords

Cite

@article{arxiv.1207.5284,
  title  = {Character Varieties of Abelian Groups},
  author = {Adam S. Sikora},
  journal= {arXiv preprint arXiv:1207.5284},
  year   = {2015}
}

Comments

to appear in Math. Z., 18 pages, 1 figure

R2 v1 2026-06-21T21:39:46.105Z