Category theory is a branch of abstract algebra with incredibly diverse applications. This text and reference book is aimed not only at mathematicians, but also researchers and students of computer science, logic, linguistics, cognitive science, philosophy, and any of the other fields in which the i[...]

When Bertrand Russell discovered an unresolvable contradiction in Gottlob Frege's (1848-1925) logical system, the effect was calamitous, embittering Frege and overshadowing his important work in analytical philosophy. Frege's student, Rudolf Carnap, took detailed notes of his lectures that show how [...]