Variable Neighborhood Search for the Cost Constrained Minimum Label Spanning Tree and Label Constrained Minimum Spanning Tree Problems

The Minimum Label Spanning Tree (MLST) problem was introduced by Chang and Leu [2].In this problem, we are given an undirected graph G = (V,E) with labeled edges; each edge has a single label from the set of labels L and different edges can have the same label. The objective is to find a spanning tree with the minimum number of distinct labels. The MLST is motivated from appli