A Polynomial Time Algorithm for Inferring Grammars for Mildly Context Sensitive Languages

Natural languages are largely context-sensitive, yet context-sensitive grammars cannot be identified in the limit from positive examples [Gold, 1967]. Mildly context-sensitive languages are able to express the most common context-sensitive structures found in natural language. We restrict our view to a class of mildly context-sensitive languages which can be described by simple external contextual grammars. We present the first polynomialtime algorithm for inferring these grammars from positive data.