Abstract For any infinite‐type surface , a natural question is whether the homology of its mapping class group contains any non‐trivial classes that are supported on (i) a compact subsurface; or (ii) a finite‐type subsurface. Our purpose here is to study this question, in particular giving an almost‐complete answer when the genus of is positive (including infinite) and a partial answer when the genus of is zero. Our methods involve the notion of shiftable subsurfaces as well as homological stability for mapping class groups of finite‐type surfaces.
Palmer et al. (Thu,) studied this question.