Abstract

The last January I was in a meeting in Campinas University. The organizers of that meeting asked me to give a talk on some open problems. I accepted and I select 12 of the open problems that I dedicated some time and I cannot solved. The first 4 are not stated by me. In general are not very easy problems (specially the first 3 problems). But I hope that some of them (specially the last ones) will be solved in a near future.