Centers of subgroups of big mapping class groups and the Tits alternative
Centers of subgroups of big mapping class groups and the Tits alternative
In this note we show that many subgroups of mapping class groups of infinite-type surfaces without boundary have trivial centers, including all normal subgroups.Using similar techniques, we show that every nontrivial normal subgroup of a big mapping class group contains a nonabelian free group.In contrast, we show that no big …