Let G be a connected graph.We denote by σ(G,x)and δ(G)respectively the σ-polynomial and the edge-density of G,wher δ(G)=|E(G)|/(2^V(G)|).If σ(G,x)has at least an unreal
In this paper, the existence of strictly positive solutions for N species normutonomous Kolmogorov competition systems is studied. By applying the Schauder'
The purpose of this paper is to investigate a new type of evolution problem for closedconvex plane curves which will preserves the perimeter of the curve but ex