For that my (classical) favorites are #PeircesLaw and #Leibniz's #PraeclarumTheorema.
Here's how they look in a variant of #Peirce's #AlphaGraphs.
• https://inquiryintoinquiry.com/2008/10/06/peirces-law/
• https://inquiryintoinquiry.com/2008/10/05/praeclarum-theorema/
#alphagraphs #Peirce #praeclarumtheorema #leibniz #peirceslaw