Balanced problems on graphs with categorization of edges

Suppose a graph G = (V, E) with edge weights w(e) and edges partitioned into disjoint categories S1, . . . , Sp is given. We consider optimization problems P on G defined by a family of feasible sets D(G) and the following objective function: L5(D) = max 1≤i≤p ( max e∈Si∩D w(e)− min e∈Si∩D w(e) ) For an arbitrary number of categories we show that the L5-perfect matching, L5-a-b path, L5-spanning tree problems and L5-Hamilton cycle (on a Halin graph) problem are NP-complete. We also summarize polynomiality results concerning above objective functions for arbitrary and for fixed number of categories.