トポロジーセミナー(北山貴裕 氏,10月4日)

場所:筑波大学 自然系学系D棟 D509
講演者:北山貴裕 氏 (京都大学 数理解析研究所)
講演題目:On an analogue of Culler-Shalen theory for higher dimensional representations
Culler and Shalen established a way to construct incompressible surfaces
in a 3-manifold from ideal points of the SL_2-character variety.
We present an analogous theory to construct certain kinds of
branched surfaces from limit points of the SL_n-character variety.
Such a branched surface induces a nontrivial presentation of
the fundamental group as a 2-dimensional complex of groups.
This is a joint work with Takashi Hara (Osaka University).