{ "id": "1909.06729", "version": "v1", "published": "2019-09-15T04:19:29.000Z", "updated": "2019-09-15T04:19:29.000Z", "title": "$g$-vectors of manifolds with boundary", "authors": [ "Isabella Novik", "Ed Swartz" ], "categories": [ "math.CO" ], "abstract": "We extend several $g$-type theorems for connected, orientable homology manifolds without boundary to manifolds with boundary. As applications of these results we obtain K\\\"uhnel-type bounds on the Betti numbers as well as on certain weighted sums of Betti numbers of manifolds with boundary. Our main tool is the completion $\\hat\\Delta$ of a manifold with boundary $\\Delta$; it is obtained from $\\Delta$ by coning off the boundary of $\\Delta$ with a single new vertex. We show that despite the fact that $\\hat{\\Delta}$ has a singular vertex, its Stanley--Reisner ring shares a few properties with the Stanley--Reisner rings of homology spheres. We close with a discussion of a connection between three lower bound theorems for manifolds, PL-handle decompositions, and surgery.", "revisions": [ { "version": "v1", "updated": "2019-09-15T04:19:29.000Z" } ], "analyses": { "subjects": [ "05E45", "52B05", "13F55" ], "keywords": [ "betti numbers", "lower bound theorems", "pl-handle decompositions", "main tool", "type theorems" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }