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  2. Tautology (logic) - Wikipedia

    en.wikipedia.org/wiki/Tautology_(logic)

    The method of truth tables illustrated above is provably correct – the truth table for a tautology will end in a column with only T, while the truth table for a sentence that is not a tautology will contain a row whose final column is F, and the valuation corresponding to that row is a valuation that does not satisfy the sentence being tested.

  3. Propositional calculus - Wikipedia

    en.wikipedia.org/wiki/Propositional_calculus

    A truth table is a semantic proof method used to determine the truth value of a propositional logic expression in every possible scenario. [93] By exhaustively listing the truth values of its constituent atoms, a truth table can show whether a proposition is true, false, tautological, or contradictory. [94] See § Semantic proof via truth tables.

  4. Method of analytic tableaux - Wikipedia

    en.wikipedia.org/wiki/Method_of_analytic_tableaux

    A graphical representation of a partially built propositional tableau. In proof theory, the semantic tableau [1] (/ t æ ˈ b l oʊ, ˈ t æ b l oʊ /; plural: tableaux), also called an analytic tableau, [2] truth tree, [1] or simply tree, [2] is a decision procedure for sentential and related logics, and a proof procedure for formulae of first-order logic. [1]

  5. Truth table - Wikipedia

    en.wikipedia.org/wiki/Truth_table

    A truth table is a mathematical table used in logic—specifically in connection with Boolean algebra, Boolean functions, and propositional calculus—which sets out the functional values of logical expressions on each of their functional arguments, that is, for each combination of values taken by their logical variables. [1]

  6. List of rules of inference - Wikipedia

    en.wikipedia.org/wiki/List_of_rules_of_inference

    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.

  7. Tautology (rule of inference) - Wikipedia

    en.wikipedia.org/wiki/Tautology_(rule_of_inference)

    In propositional logic, tautology is either of two commonly used rules of replacement. [ 1 ] [ 2 ] [ 3 ] The rules are used to eliminate redundancy in disjunctions and conjunctions when they occur in logical proofs .

  8. Tautological consequence - Wikipedia

    en.wikipedia.org/wiki/Tautological_consequence

    Tautological consequence can also be defined as ∧ ∧ ... ∧ → is a substitution instance of a tautology, with the same effect. [2]It follows from the definition that if a proposition p is a contradiction then p tautologically implies every proposition, because there is no truth valuation that causes p to be true and so the definition of tautological implication is trivially satisfied.

  9. Propositional formula - Wikipedia

    en.wikipedia.org/wiki/Propositional_formula

    A truth table reveals the rows where inconsistencies occur between p = q delayed at the input and q at the output. After "breaking" the feed-back, [27] the truth table construction proceeds in the conventional manner. But afterwards, in every row the output q is compared to the now-independent input p and any inconsistencies between p and q are ...