I thought the CatNet would be interested in the following question which appeared on <newsgroup sci.math>. The letter was pointed out to me by a colleague at Macquarie. --Ross ************************************************* From: mathwft@math.canterbury.ac.nz (Bill Taylor) Newsgroups: sci.math Subject: Query about Category Theory. Date: 18 Jun 2000 05:36:30 GMT Organization: Department of Mathematics and Statistics, University of Canterbury, Christchurch, NewZealand Does anyone know of any cases where Category Theory (morphisms, functors & all that) has helped solve an unsolved problem? That is, a problem in some other branch of math, posed without reference to categorical ideas, and previously unsolved, that was first solved via Category T. I realize that CT provides a unifying framework for many seemingly disparate ideas in math, and that is a fine thing of course; but I was just wondering if it had this problem-solving capability. TIA for any helpful responses. ---------------------------------------------------------------------------- --- Bill Taylor W.Taylor@math.canterbury.ac.nz