A discontinuity in pattern inference

Abstract

This paper examines the learnability of a major subclass of E-pattern languages - also known as erasing or extended pattern languages - in Gold's learning model: We show that the class of terminal-free E-pattern languages is inferrable from positive data if the corresponding terminal alphabet consists of three or more letters. Consequently, the recently presented negative result for binary alphabets is unique. © Springer-Verlag 2004.