Tree transformation system in machine translation system

Abstract

A mechanical translation system is provided to obtain a sentence of target language from the tree expression of source language. The processing progresses as follows: First, a pattern which coincides with partial structure, including the highest node, of the tree fragment chosen, is selected among patterns previously contained in the pattern dictionary. The pattern has a production rule attached to the pattern. The production rule takes 'extraction information' which is composed of information in the source language tree fragment concerning the part outside of and under the above mentioned partial structure and 'instruction information' which is attached to the highest node of the tree fragment, as input information and generates a tree fragment in target language corresponding to the source language tree fragment and also 'instruction information' to be attached to the border nodes of the partial structure and other parts in the source language tree fragment which consists of memorizing the target language tree fragment and erasing the partial structure from the source language tree fragment and bringing back to the memory to contain target language tree fragments, thus produced normally plural 'child' tree fragments. After processing a plurality of target language tree fragments contained in the corresponding memory and uniting them into a single tree producing the tree of target language tree, from which the sentence in target language is obtained immediately.