INSTITUTO POLITÉCNICO NACIONAL CENTRO DE INVESTIGACIÓN EN COMPUTACIÓN NATURAL LANGUAGE PROCESSING LABORATORY WORD SENSE DISAMBIGUATION AND RECOGNIZING TEXTUAL ENTAILMENT WITH STATISTICAL METHODS A THESIS IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN COMPUTER SCIENCE BY: Miguel Angel Ríos Gaona ADVISORS: Dr. Alexander Gelbukh Dr. Sivaji Bandyopadhyay MEXICO, D.F., 2010