{ "id": "2102.00984", "version": "v1", "published": "2021-02-01T17:07:59.000Z", "updated": "2021-02-01T17:07:59.000Z", "title": "Faulty picture-hanging improved", "authors": [ "Johan Wästlund" ], "comment": "14 pages, 3 figures", "categories": [ "cs.DM", "math.CO" ], "abstract": "A picture-hanging puzzle is the task of hanging a framed picture with a wire around a set of nails in such a way that it can remain hanging on certain specified sets of nails, but will fall if any more are removed. The classical brain teaser asks us to hang a picture on two nails in such a way that it falls when any one is detached. Demaine et al (2012) proved that all reasonable puzzles of this kind are solvable, and that for the $k$-out-of-$n$ problem, the size of a solution can be bounded by a polynomial in $n$. We give simplified proofs of these facts, for the latter leading to a reasonable exponent in the polynomial bound.", "revisions": [ { "version": "v1", "updated": "2021-02-01T17:07:59.000Z" } ], "analyses": { "subjects": [ "05A05", "G.2.1", "G.3" ], "keywords": [ "faulty picture-hanging", "classical brain teaser asks", "polynomial bound", "specified sets", "framed picture" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable" } } }