“Semeiotic” is a term used by Charles Sanders Peirce that serves to distinguish his theory of triadic sign relations from other approaches to the same subject matter, more generally referred to as “semiotics”.
Logical graphs are next presented as a formal system by going back to the initial elements and developing their consequences in a systematic manner.
The praeclarum theorema, or splendid theorem, is a theorem of propositional calculus that was noted and named by G.W. Leibniz.
Hypostatic Abstraction (HA) is a formal operation on a subject–predicate form that preserves its information while introducing a new subject and upping the “arity” of its predicate. To cite a notorious example, HA turns “Opium is drowsifying” into “Opium has dormitive virtue”.
Peirce’s law is a logical proposition that states a non-obvious truth of classical logic and affords a novel way of defining classical propositional calculus.
The logic of relatives, more precisely, the logic of relative terms, is the study of relations as represented in symbolic forms known as “rhemes”, “rhemata”, or “relative terms”.
Differential logic is the logic of variation — the logic of change and difference.
A logical graph is a graph-theoretic structure in one of the styles of graphical syntax that Charles Sanders Peirce developed for logic.
The pragmatic maxim is a guideline for the practice of inquiry formulated by Charles Sanders Peirce. Serving as a normative recommendation or a regulative principle in the normative science of logic, its function is to guide the conduct of thought toward the achievement of its aims, advising the addressee on an optimal way of “attaining clearness of apprehension”.