A characterization for graphs having strong parity factors

TL;DR

This paper characterizes graphs with the strong parity property, disproves a previous conjecture that all 2-edge-connected graphs with minimum degree three have this property, and provides a counterexample.

Contribution

It offers a complete characterization of graphs with the strong parity property and refutes an existing conjecture by constructing a counterexample.

Findings

Provided a characterization criterion for strong parity graphs.

Disproved the conjecture that all 2-edge-connected graphs with minimum degree three have the property.

Constructed a specific counterexample graph.

Abstract

A graph $G$ has the \emph{strong parity property} if for every subset $X\subseteq V$ with $|X|$ even, $G$ has a spanning subgraph $F$ with minimum degree at least one such that $d_F(v)\equiv 1\pmod 2$ for all $v\in X$, $d_F(y)\equiv 0\pmod 2$ for all $y\in V(G)-X$. Bujt\'as, Jendrol and Tuza (On specific factors in graphs, \emph{Graphs and Combin.}, 36 (2020), 1391-1399.) introduced the concept and conjectured that every 2-edge-connected graph with minimum degree at least three has the strong parity property. In this paper, we give a characterization for graphs to have the strong parity property and construct a counterexample to disprove the conjecture proposed by Bujt\'as, Jendrol and Tuza.