This article develops elementary facts about the formal calculi that we describe as '''propositional equation reasoning systems''' ('''PERS'''). This work follows up on the ''[[alpha graphs]]'' that [[Charles Sanders Peirce]] devised as a graphical syntax for [[propositional calculus]] and also on the ''calculus of indications'' that [[George Spencer Brown]] presented in his ''[[Laws of Form]]''. | This article develops elementary facts about the formal calculi that we describe as '''propositional equation reasoning systems''' ('''PERS'''). This work follows up on the ''[[alpha graphs]]'' that [[Charles Sanders Peirce]] devised as a graphical syntax for [[propositional calculus]] and also on the ''calculus of indications'' that [[George Spencer Brown]] presented in his ''[[Laws of Form]]''. |