Interpolation and Amalgamation for Arrays with MaxDiff

Abstract In this paper, the theory of McCarthy’s extensional arrays enriched with a maxdiff operation (this returns biggest index where two given differ) is proposed. It known from literature that diff required for in order to enjoy Craig interpolation property at quantifier-free level. However, introduced merely instrumental purpose and has only purely formal meaning (it obtained Skolemization extensionality axiom). Our significantly increases level expressivity; however, obtaining results resulting becomes surprisingly hard task. We obtain such via thorough semantic analysis models their amalgamation properties. The are modular respect it shown how convert them into concrete algorithms hierarchical approach.