Formal Notation
The biconditional elimination rule may be written in sequent notation:
and
where is a metalogical symbol meaning that, in the first case, and in the other are syntactic consequences of in some logical system;
or as the statement of a truth-functional tautology or theorem of propositional logic:
where, and are propositions expressed in some formal system.
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Famous quotes containing the word formal:
“It is in the nature of allegory, as opposed to symbolism, to beg the question of absolute reality. The allegorist avails himself of a formal correspondence between ideas and things, both of which he assumes as given; he need not inquire whether either sphere is real or whether, in the final analysis, reality consists in their interaction.”
—Charles, Jr. Feidelson, U.S. educator, critic. Symbolism and American Literature, ch. 1, University of Chicago Press (1953)