logic connective
41Sequent calculus — In proof theory and mathematical logic, sequent calculus is a family of formal systems sharing a certain style of inference and certain formal properties. The first sequent calculi, systems LK and LJ, were introduced by Gerhard Gentzen in 1934 as …
42Functional completeness — In logic, a functionally complete set of logical connectives or Boolean operators is one which can be used to express all possible truth tables by combining members of the set into a Boolean expression.[1][2] A well known complete set of… …
43Propositional variable — In mathematical logic, a propositional variable (also called a sentential variable or sentential letter) is a variable which can either be true or false. Propositional variables are the basic building blocks of propositional formulas, used in… …
44Atomic formula — In mathematical logic, an atomic formula (also known simply as an atom) is a formula with no deeper propositional structure, that is, a formula that contains no logical connectives or equivalently a formula that has no strict subformulas. Atoms… …
45Counterfactual conditional — For other uses, see Counterfactual (disambiguation). A counterfactual conditional, subjunctive conditional, or remote conditional, abbreviated cf, is a conditional (or if then ) statement indicating what would be the case if its antecedent were… …
46Truth function — Truth functional redirects here, for the truth functional conditional, see Material conditional. In mathematical logic, a truth function is a function from a set of truth values to truth values. Classically the domain and range of a truth… …
47Peirce's law — in logic is named after the philosopher and logician Charles Sanders Peirce. It was taken as an axiom in his first axiomatisation of propositional logic. In propositional calculus, Peirce s law says that (( P → Q )→ P )→ P . Written out, this… …
48Henry M. Sheffer — Henry Maurice Sheffer (1882 1964) was an American logician.Sheffer was a Polish Jew born in the Ukraine, who immigrated to the USA with his parents. He was educated at Harvard University, learning logic from Josiah Royce. Sheffer spent most of… …
49Boolean algebra — /booh lee euhn/ 1. Logic. a deductive logical system, usually applied to classes, in which, under the operations of intersection and symmetric difference, classes are treated as algebraic quantities. 2. Math. a ring with a multiplicative identity …
50Willard Van Orman Quine — Unreferenced|date=August 2007 Infobox Philosopher region = Western Philosophy era = 20th century philosophy color = #B0C4DE image caption = Willard Van Orman Quine name = Willard Van Orman Quine birth = birth date|mf=yes|1908|6|25 death = death… …
