2021/09/07 by Lu, Yong, Wu, Qi
#Combinatorics (math.CO) #FOS: Mathematics
paper · doi:10.48550/arxiv.2109.02830
Let Γ=(G,σ) be a signed graph and A(G,σ) be its adjacency matrix. Denote by gr(G) the girth of G, which is the length of the shortest cycle in G. Let r(G,σ) be the rank of (G,σ). In this paper, we will prove that r(G,σ)≥ gr(G)-2 for a signed graph (G,σ). Moreover, we characterize all extremal graphs which satisfy the equalities r(G,σ)=gr(G)-2 and r(G,σ)=gr(G).