In this book, Paulo Guilherme Santos studies diagonalization in formal mathematics from logical aspects to everyday mathematics. He starts with a study of the diagonalization lemma and its relation to the strong diagonalization lemma. After that, Yablos paradox is examined, and a self-referential interpretation is given. From that, a general structure of diagonalization with paradoxes is presented. Finally, the author studies a general theory of diagonalization with the help of examples from mathematics.

Paulo Guilherme Santos is currently a PhD student at FCT, Universidade Nova de Lisboa, Portugal and at University of Tubingen, Germany. His field of work is logic, e.g. formal arithmetic, provability logic, provability predicates, and paradoxes.

Diagonalization in Mathematics.- Diagonalization Lemma.- Fixed Point Theorems.- Paradoxes: Liar, Yablos Paradox, Currys Paradox.