A Note on Signed k-Submatching in Graphs

TL;DR

This paper investigates the signed k-submatching number in graphs, proving a lower bound related to graph components and providing a formula for the maximum case, thereby settling a conjecture by Wang.

Contribution

It establishes a lower bound for the signed k-submatching number and offers a formula for computing it, confirming a conjecture in graph theory.

Findings

Proved that eta_S^k(G)  n - k - ardinality of components of G.

Derived a formula for eta_S^n(G).

Settled a conjecture proposed by Wang.

Abstract

Let $G$ be a graph of order $n$. For every $v\in V(G)$, let $E_G(v)$ denote the set of all edges incident with $v$. A signed $k$-submatching of $G$ is a function $f:E(G)\longrightarrow \{-1,1\}$, satisfying $f(E_G(v))\leq 1$ for at least $k$ vertices, where $f(S)=\sum_{e\in S}f(e)$, for each $ S\subseteq E(G)$. The maximum of the value of $f(E(G))$, taken over all signed $k$-submatching $f$ of $G$, is called the signed $k$-submatching number and is denoted by $\beta ^k_S(G)$. In this paper, we prove that for every graph $G$ of order $n$ and for any positive integer $k \leq n$, $\beta ^k_S (G) \geq n-k - \omega(G)$, where $w(G)$ is the number of components of $G$. This settles a conjecture proposed by Wang. Also, we present a formula for the computation of $\beta_S^n(G)$.