Formal Notation
The disjunctive syllogism rule may be written in sequent notation:
where is a metalogical symbol meaning that is a syntactic consequence of, and in some logical system;
and expressed as a truth-functional tautology or theorem of propositional logic:
where, and are propositions expressed in some formal system.
Read more about this topic: Disjunctive Syllogism
Famous quotes containing the word formal:
“True variety is in that plenitude of real and unexpected elements, in the branch charged with blue flowers thrusting itself, against all expectations, from the springtime hedge which seems already too full, while the purely formal imitation of variety ... is but void and uniformity, that is, that which is most opposed to variety....”
—Marcel Proust (1871–1922)