The C-complex clasp number of links

Jonah Amundsen; Eric Anderson; Christopher William Davis; Daniel Guyer

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arXiv · 1907.12472

The C-complex clasp number of links

Jonah Amundsen·Eric Anderson·Christopher William Davis·Daniel Guyer

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Abstract

In the 1980's Daryl Cooper introduced the notion of a C-complex (or clasp-complex) bounded by a link and explained how to compute signatures and polynomial invariants using a C-complex. Since then this was extended by works of Cimasoni, Florens, Mellor, Melvin, Conway, Toffoli, Friedl, and others to compute other link invariants. Informally a C-complex is a union of surfaces which are allowed to intersect each other in clasps. The purpose of the current paper is to study the minimal number of clasps amongst all C-complexes bounded by a fixed link $L$. This measure of complexity is related to the number of crossing changes needed to reduce $L$ to a boundary link. We prove that if $L$ is a 2-component link with nonzero linking number, then the linking number determines the minimal number of clasps amongst all C-complexes. In the case of 3-component links, the triple linking number provides an additional lower bound on the number of clasps in a C-complex.

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BibTeX RIS

Jonah Amundsen, Eric Anderson, Christopher William Davis, Daniel Guyer. 2019-07-29. The C-complex clasp number of links. https://arxiv.org/abs/1907.12472

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