On the crossing number of knots and links on surface in 3-manifolds

Tetsuya Ito

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arXiv · 2606.18776

On the crossing number of knots and links on surface in 3-manifolds

Tetsuya Ito

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Abstract

We give a lower bound of the minimum crossing number of knots and links projected on a 2-sided surface in a 3-manifold using the rank of fundamental groups which means that the crossing number can take arbitrary large values. On the contrary, we show that for a branched surface, the minimum crossing number is always zero. As an application, we give an upper bound of the three-page index by the crossing number.

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Tetsuya Ito. 2026-06-17. On the crossing number of knots and links on surface in 3-manifolds. https://arxiv.org/abs/2606.18776

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