{ "id": "1807.08384", "version": "v1", "published": "2018-07-22T23:34:58.000Z", "updated": "2018-07-22T23:34:58.000Z", "title": "Lattices with many congruences are planar", "authors": [ "Gábor Czédli" ], "comment": "10 pages, 2 figures", "categories": [ "math.CO" ], "abstract": "Let $L$ be an $n$-element finite lattice. We prove that if $L$ has strictly more than $2^{n-5}$ congruences, then $L$ is planar. This result is sharp, since for each natural number $n\\geq 8$, there exists a non-planar lattice with exactly $2^{n-5}$ congruences.", "revisions": [ { "version": "v1", "updated": "2018-07-22T23:34:58.000Z" } ], "analyses": { "subjects": [ "06B10" ], "keywords": [ "congruences", "element finite lattice", "non-planar lattice" ], "note": { "typesetting": "TeX", "pages": 10, "language": "en", "license": "arXiv", "status": "editable" } } }