Congruence subgroup problem for mapping class groups

Congruence subgroup problem for mapping class groups

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Ben McReynolds, University of Chicago
Fine Hall 314

I will discuss the congruence subgroup problem for mapping class groups, a problem that generalizes the classical one for arithmetic groups. I will discuss an unpublished proof by W. Thurston for an affirmative answer to this problem for genus zero mapping class groups. Time permitting, I will discuss the current state of this problem.