Classical combinatorial optimization concerns finding a feasible subset of ground set in order to optimize an objective function. We address this article the inverse problem with k-max In other words, we attempt perturb weights elements at minimum total cost make predetermined optimal fashion respect perturbed weights. first show that is general NP-hard. Regarding case independent subsets, O(n2...

In this paper, a combinatorial reverse auction mechanism is proposed for selecting the most efficient service-providers for resolving sustained power interruptions in multiple regions of an electric power distribution company’s responsibility area. Through this mechanism, supplying the required service in each region is assigned to only one potential service-provider considering two criteria in...

It has been proved that sphericity testing for digraphs is an NP-complete problem. Here, we investigate sphericity of 3-connected single source digraphs. We provide a new combinatorial characterization of sphericity and give a linear time algorithm for sphericity testing. Our algorithm tests whether a 3-connected single source digraph with $n$ vertices is spherical in $O(n)$ time.