{ "id": "2006.09669", "version": "v1", "published": "2020-06-17T05:49:26.000Z", "updated": "2020-06-17T05:49:26.000Z", "title": "Equivariant cohomology for cyclic groups of square-free order", "authors": [ "Samik Basu", "Surojit Ghosh" ], "categories": [ "math.AT" ], "abstract": "The main objective of this paper is to compute $RO(G)$-graded cohomology of $G$-orbits for the group $G=C_n$, where $n$ is a product of distinct primes. We compute these groups for the constant Mackey functor $\\underline{Z}$ and for the Burnside ring Mackey functor $\\underline{A}$. Among other things, we show that the groups $\\underline{H}^\\alpha_G(S^0)$ are mostly determined by the fixed point dimensions of the virtual representations $\\alpha$, except in the case of $\\underline{A}$ coefficients when the fixed point dimensions of $\\alpha$ have many zeros. In the case of $\\underline{Z}$ coefficients, the ring structure on the cohomology is also described. The calculations are then used to prove freeness results for certain $G$-complexes.", "revisions": [ { "version": "v1", "updated": "2020-06-17T05:49:26.000Z" } ], "analyses": { "keywords": [ "cyclic groups", "square-free order", "equivariant cohomology", "fixed point dimensions", "burnside ring mackey functor" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }