The Shields–Harary numbers of Km,nKm,n for continuous concave cost functions vanishing at 1

It is shown that the Shields–Harary index of vulnerability of the complete bipartite graph Km,nKm,n, with respect to the cost function f(x)=1-xf(x)=1-x, 0⩽x⩽10⩽x⩽1, is m  , if n⩾m+2m, and 1n+1⌊(n+m)24⌋, if m⩽n