Unranked second-order anti-unification

Abstract

In this work we study anti-unification for unranked hedges, permitting context and hedge variables. Hedges are sequences of unranked terms. The anti-unification problem of two hedges and is concerned with finding their generalization, a hedge such that both and are substitution instances of . Second-order power is gained by using context variables to generalize vertical differences at the input hedges. Hedge variables are used to generalize horizontal differences. An anti-unification algorithm is presented, which computes a generalization of input hedges and records all the differences. The computed generalizations are least general among a certain class of generalizations. © 2014 Springer-Verlag.