On inequalities between unknotting numbers and crossing numbers of spatial embeddings of trivializable graphs and handlebody-knots

Yuta Akimoto

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arXiv · 2103.11079

On inequalities between unknotting numbers and crossing numbers of spatial embeddings of trivializable graphs and handlebody-knots

Yuta Akimoto

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Abstract

We study relations between unknotting number and crossing number of a spatial embedding of a handcuff-graph and a theta curve. It is well known that for any non-trivial knot $K$ twice the unknotting number of $K$ is less than or equal to the crossing number of $K$ minus one. We show that this is extended to handlebody-knots. We also characterize the handlebody-knots which satisfy the equality.

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Yuta Akimoto. 2021-03-20. On inequalities between unknotting numbers and crossing numbers of spatial embeddings of trivializable graphs and handlebody-knots. https://arxiv.org/abs/2103.11079

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