On the maximum twist width of delta-matroids
Abstract
For a ribbon graph , let denote its Euler genus. Recently, Chen, Gross and Tucker [J. Algebraic Combin. 63 (2026) 13] derived a formula for the maximum partial-dual Euler-genus of a ribbon graph . Their key finding is that can be achieved by a partial dual with respect to the edge set of a spanning quasi-tree. Moreover, they proposed the following problem: Given a ribbon graph , is there a sequence of edges such that and such that the sequence rises monotonically (i.e., never decreasing) to ? Delta-matroids are set systems that satisfy the symmetric exchange axiom and serve as a matroidal abstraction of ribbon graphs. In this paper, we first show that the maximum twist width of a set system can be attained by twisting one of its feasible sets, which extends the result of Chen, Gross and Tucker to set systems. Then we solve the delta-matroid version of their problem, thereby providing an affirmative answer to the original problem for ribbon graphs.
Keywords
Cite
@article{arxiv.2602.01946,
title = {On the maximum twist width of delta-matroids},
author = {Xian'an Jin and Zhuo Li and Qi Yan and Gang Zhang},
journal= {arXiv preprint arXiv:2602.01946},
year = {2026}
}