Department of Computer, Control and Management Engineering

When looking for a propositional abductive explanation of a given set of manifestations, an ordering between possible solutions is often assumed. While the complexity of computing optimal solutions is already known, in this paper we consider second-best solutions with respect to different orderings, and different definitions of what a second-best solution is: an optimal solution not already found, or a solution that is optimal among the ones not previously found. © 2015 Elsevier Inc. Allrightsreserved.