Non-structural Subtype Entailment in Automata Theory

Decidability of non-structural subtype entailment is a long standing open problem in programming language theory. In this paper, we apply automata theoretic methods to characterize the problem equivalently by using regular expressions and word equations. This characterization induces new results on nonstructural subtype entailment, constitutes a promising starting point for further investigations on decidability, and explains for the first time why the problem is so difficult. The difficulty is caused by implicit word equations that we make explicit.

• Type: Conference
• Year: 2001
• Where: TACS
• Authors: Joachim Niehren, Tim Priesnitz
• Keywords: Non-structural Subtype Entailment, Nonstructural Subtype Entailment, Software Engineering, Subtype Entailment, TACS 2001