Tonight I discovered that I have been working the whole week, under a false assumption, trying to solve a problem with nested quantifiers. No wonder it was difficult to understand what was going on, hounestly I never figuered it out. I think this could be the real reason why I recently have been visiting slashdot a thousand times and reading/writing newsgroups without solving any real problems. Damn it was hard to consolidate and identify this problem. I wrote bunches of testcases and carefully chose the input data. Is it true that humans learn from their mistakes?