A note on maximal plane subgraphs of the complete twisted graph containing perfect matchings

Abstract

The twisted graph $T_{n}$ is a drawing of the complete graph with $n$ vertices $v_{1},v_{2},\ldots ,v_{n}$ in which two edges $v_{i}v_{j}$ ($i<j$) and $v_{s}v_{t}$ ($s<t$) cross if and only if $i<s<t<j$ or $s<i<j<t$. We show that for any maximal plane subgraphs $S$ and $R$ of $T_{n}$, each containing at least one perfect matching, there is a sequence $S=F_0, F_1, \ldots, F_m=R$ of maximal plane subgrahs of $T_n$, also containing perfect matchings, such that for $i=0,1, \ldots, m-1$, $F_{i+1}$ can be obtained from $F_{i}$ by a single edge exchange.