POLYNOMIAL-TIME INFERENCE OF PARALLELED EVEN MONOGENIC PURE CONTEXT-FREE LANGUAGES

We introduce a subclass of context-free languages, called pure context -free (PCF) languages, which is generated by context-free grammars wit h only one type of symbol (i.e., terminals and nonterminals are not di stinguished), and consider the problem of identifying paralleled even monogenic pure context-free (pem-PCF) languages, PCF languages with re stricted and enhanced Features, from positive data only. In this paper we show that the problem of identifying the class of pem-PCF language s is reduced to the problem of identifying the class of monogenic PCF (mono-PCF), whose identifiability was shown in [11], by decomposing ea ch string of pem-PCF languages. Then, with its result, we show that th e class of pem-PCF languages is polynomial time identifiable in the li mit from positive data. Further, we refer to properties of its identif ication algorithm.