Almost positive links are strongly quasipositive

Autor: Peter Feller, Lukas Lewark, Andrew Lobb
Rok vydání: 2023
Předmět:
Zdroj: Mathematische annalen, 2023, Vol.385(1-2), pp.481-510 [Peer Reviewed Journal]
Mathematische Annalen, 385 (1)
Feller, Peter; Lewark, Lukas; Lobb, Andrew (2023). Almost positive links are strongly quasipositive. Mathematische Annalen, 385(1-2), pp. 481-510. Springer 10.1007/s00208-021-02328-x
ISSN: 1432-1807
0025-5831
DOI: 10.1007/s00208-021-02328-x
Popis: We prove that any link admitting a diagram with a single negative crossing is strongly quasipositive. This answers a question of Stoimenow's in the (strong) positive. As a second main result, we give a simple and complete characterization of link diagrams with quasipositive canonical surface (the surface produced by Seifert's algorithm). As applications, we determine which prime knots up to 13 crossings are strongly quasipositive, and we confirm the following conjecture for knots that have a canonical surface realizing their genus: a knot is strongly quasipositive if and only if the Bennequin inequality is an equality.
Mathematische Annalen, 385 (1)
ISSN:1432-1807
ISSN:0025-5831
Databáze: OpenAIRE
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