Logical graph

A logical graph is a special type of diagrammatic structure of graphical syntax developed for logic (such as those developed by Charles Sanders Peirce). In his papers on qualitative logic, entitative graphs, and existential graphs, Peirce developed several versions of a graphical formalism, or a graph-theoretic formal language, designed to be interpreted for logic. In the century since Peirce initiated this line of development, a variety of formal graph-theoretic structures that have branched out from what is abstractly the same formal base.