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In propositional logic, material implication [1] [2] is a valid rule of replacement that allows a conditional statement to be replaced by a disjunction in which the antecedent is negated. The rule states that P implies Q is logically equivalent to not- P {\displaystyle P} or Q {\displaystyle Q} and that either form can replace the other in ...
It is the negation of material implication. That is to say that for any two propositions P {\displaystyle P} and Q {\displaystyle Q} , the material nonimplication from P {\displaystyle P} to Q {\displaystyle Q} is true if and only if the negation of the material implication from P {\displaystyle P} to Q {\displaystyle Q} is true.
14, OR, Logical disjunction; 15, true, Tautology. Each logic operator can be used in an assertion about variables and operations, showing a basic rule of inference. Examples: The column-14 operator (OR), shows Addition rule: when p=T (the hypothesis selects the first two lines of the table), we see (at column-14) that p∨q=T.
The name "disjunctive syllogism" derives from its being a syllogism, a three-step argument, and the use of a logical disjunction (any "or" statement.) For example, "P or Q" is a disjunction, where P and Q are called the statement's disjuncts. The rule makes it possible to eliminate a disjunction from a logical proof. It is the rule that
where is a metalogical symbol meaning that is a syntactic consequence of , in the one case, in the other, in some logical system; or as a rule of inference : P ∨ P ∴ P {\displaystyle {\frac {P\lor P}{\therefore P}}}
Rekhta is an Indian web portal started by Rekhta Foundation, a non-profit organisation dedicated to the preservation and promotion of the Urdu literature. [4] The Rekhta Library Project, its books preservation initiative, has successfully digitized approximately 200,000 books over a span of ten years. [5]
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Theories over constructive logics can exhibit the disjunction property. The pure intuitionistic propositional calculus does so as well. In particular, it means the excluded middle disjunction for an un-rejectable statement is provable exactly when is provable. This also means, for examples, that the excluded middle disjunction for some the ...