{ "id": "2102.00412", "version": "v1", "published": "2021-01-31T08:37:47.000Z", "updated": "2021-01-31T08:37:47.000Z", "title": "One Curious Identity Counting Graceful Labelings", "authors": [ "Nikolai Beluhov" ], "comment": "16 pages", "categories": [ "math.CO" ], "abstract": "Let $a$ and $b$ be positive integers with prime factorisations $a = p_1^np_2^n$ and $b = q_1^nq_2^n$. We prove that the number of essentially distinct $\\alpha$-graceful labelings of the complete bipartite graph $K_{a, b}$ equals the alternating sum of fourth powers of binomial coefficients $(-1)^n[\\binom{2n}{0}^4 - \\binom{2n}{1}^4 + \\binom{2n}{2}^4 - \\binom{2n}{3}^4 + \\cdots + \\binom{2n}{2n}^4]$.", "revisions": [ { "version": "v1", "updated": "2021-01-31T08:37:47.000Z" } ], "analyses": { "subjects": [ "05A19", "05C30", "05C78" ], "keywords": [ "curious identity counting graceful labelings", "complete bipartite graph", "prime factorisations", "fourth powers", "binomial coefficients" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable" } } }