Self-intersection numbers of curves on the punctured torus

dc.creatorChas, Moira
dc.creatorPhillips, Anthony
dc.date2009-01-20
dc.date.accessioned2026-07-07T12:32:06Z
dc.date.available2026-07-07T12:32:06Z
dc.descriptionThe minimum number of self-intersection points for members of a free homotopy class of curves on the punctured torus is bounded above in terms of the number L of letters required for a minimal description of the class in terms of the generators of the fundamental group and their inverses: it is less than or equal to (L-2)^2/4 if L is even, and (L-1)(L-3)/4 if L is odd. The classes attaining this bound are explicitly described in terms of the generators; there are (L-2)^2 + 4 of them if L is even, and 2(L-1)(L-3) + 8 if L is odd; similar descriptions and totals are given for classes with self-intersection number equal to one less than the maximum. Proofs use both combinatorial calculations and topological operations on representative curves. Computer-generated data are tabulated counting, for each non-negative integer, how many length-L classes have that self-intersection number, for each length L less than or equal to 12. Experimental data are also presented for the pair-of-pants surface.
dc.description39 pages, 8 figures
dc.identifierhttps://arxiv.org/abs/0901.2974
dc.identifierhttp://arxiv.org/abs/0901.2974
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/216671
dc.subjectGeometric Topology
dc.subject57M05, 57N50
dc.titleSelf-intersection numbers of curves on the punctured torus
dc.typetext

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