{ "id": "2101.04588", "version": "v1", "published": "2021-01-12T16:39:00.000Z", "updated": "2021-01-12T16:39:00.000Z", "title": "Distance $4$ curves on closed surfaces of arbitrary genus", "authors": [ "Sreekrishna Palaparthi", "Kuwari Mahanta" ], "comment": "14 pages, 18 figures", "categories": [ "math.GT" ], "abstract": "Let $S_g$ denote a closed, orientable surface of genus $g \\geq 2$ and $\\mathcal{C}(S_g)$ the associated curve complex. The mapping class group of $S_g$ acts on $\\mathcal{C}(S_g)$ by isometries. Since Dehn twists about certain curves generate the mapping class group of $S_g$, one can ask how Dehn twists move specific vertices in $\\mathcal{C}(S_g)$ away from themselves. In this article, we answer this question for a specific case when the vertices are at a distance $3$. We show that if two curves represent vertices at a distance $3$ in $\\mathcal{C}(S_g)$ then the Dehn twist of one curve about another yields two vertices at distance $4$. This produces many examples of curves on $S_g$ which are at distance $4$ in $\\mathcal{C}(S_g)$. We also show that the minimum intersection number of any two curves at a distance $4$ on $S_g$, $i_{min}(g,4) \\leq (2g-1)^2$.", "revisions": [ { "version": "v1", "updated": "2021-01-12T16:39:00.000Z" } ], "analyses": { "subjects": [ "57M60", "20F65", "20F67" ], "keywords": [ "arbitrary genus", "closed surfaces", "mapping class group", "dehn twists move specific vertices", "minimum intersection number" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable" } } }