18. The computer-readable recording medium according to claim 10 , wherein the predicate-argument structure includes a predicate included in the first text or the second text, a word serving as an argument of the predicate, and a word indicating the type of argument, and, in the step (a), the predicate and the word serving as the argument of the predicate are used to generate the vector.
10. A computer-readable recording medium having recorded thereon a program for determining whether a first text entails a second text by a computer, the program including an instruction for causing the computer to execute the steps of: (a) generating, for each of the first text and the second text, a vector for each predicate-argument structure of the first text and the second text by using a word other than a word indicating the type of argument of a predicate in the predicate-argument structure; (b) comparing the vector generated for each predicate-argument structure for the first text and the vector generated for each predicate-argument structure for the second text, and identifying combinations of the predicate-argument structures of the first text and the predicate-argument structure of the second text based on a result of the comparison; and (c) obtaining a feature amount for each of the identified combinations, and determining whether the first text entails the second text based on the obtained feature amounts.