Let G be a graph and τ : V (G) → N be an assignment of thresholds to the vertices ofG. A subset of verticesD is said to be dynamic monopoly (or simply dynamo) if the vertices of G can be partitioned into subsets D0,D1, . . . ,Dk such that D0 = D and for any i = 1, . . . , k − 1 each vertex v in Di+1 has at least t(v) neighbors in D0∪ . . .∪Di. Dynamic monopolies are in fact modeling the irrever...

Introduction Much of what has been called in the Economics literature “natural” monopolies is now evolving into varying forms of open competition. Such development raises interesting questions for pricing, appropriate extent of deregulation, and in particular the use of market information by different stakeholders. Monopolies that depend on legislation to be sustainable, whenever deregulated, w...

A graph G is said to be a k-degenerate graph if any subgraph of G contains a vertex of degree at most k. Let κ be any non-negative function on the vertex set of G. We first define a κ-degenerate graph. Next we give an efficient algorithm to determine whether a graph is κ-degenerate. We revisit the concept of dynamic monopolies in graphs. The latter notion is used in formulation and analysis of ...

This paper analyses whether scale economies exists in the UK telecommunications industry. The approach employed differs from other UK studies in that panel data for a range of companies is used. This increases the number of observations and thus allows potentially for more robust tests for global subadditivity of the cost function. The main findings from the study reveal that although the resul...