Here are blog and wiki versions of an article I wrote on Peirce’s Law, an axiom or theorem (depending on your choice of logical basis) that distinguishes classical from intuitionistic propositional calculus. Aside from its pivotal logical status it affords a nice illustration of several important features of logical graphs in the style of Peirce and Spencer Brown.
- Peirce’s Law • This Blog • OEIS Wiki • InterSciWiki • MyWikiBiz • Wikiversity