Segment number of knots
Geometric Topology
2026-02-19 v2
Abstract
We introduce a new numerical knot invariant, termed the \textit{segment number}, which is derived from partitioned knot diagrams subject to specific over/under-crossing constraints. We prove that a knot is non-trivial if and only if its segment number is at least 3. Furthermore, we investigate the structural properties of the directed graph associated with a minimal segment number presentation. Specifically, we show that for any minimal presentation, the underlying graph is connected and cannot be a path. Finally, we discuss the relationship between the segment number and the bridge number, providing bounds and conjectures for future study. We also conjecture that the bridge number provides a lower bound for the segment number.
Keywords
Cite
@article{arxiv.0705.4348,
title = {Segment number of knots},
author = {Makoto Ozawa},
journal= {arXiv preprint arXiv:0705.4348},
year = {2026}
}