Much updated here: http://lesswrong.com/lw/2un/references_resources_for_lesswrong/
For example: Metamath (Constructs mathematics from scratch, starting from ZFC set theory axioms) and The Haskell Road to Logic, Maths and Programming… and check this graphic: http://space.mit.edu/home/tegmark/toe.gif
Much updated here: http://lesswrong.com/lw/2un/references_resources_for_lesswrong/
For example: Metamath (Constructs mathematics from scratch, starting from ZFC set theory axioms) and The Haskell Road to Logic, Maths and Programming… and check this graphic: http://space.mit.edu/home/tegmark/toe.gif