logic and computer science, two-variable logic is the fragment of first-order logic where formulae can be written using only two different variables....

science. First-order logic uses quantified variables over non-logical objects, and allows the use of sentences that contain variables. Rather than propositions...

mathematical logic, a propositional variable (also called a sentence letter, sentential variable, or sentential letter) is an input variable (that can either...

propositional logic, where a tautology is defined as a propositional formula that is true under any possible Boolean valuation of its propositional variables. A...

logic. Second-order logic is in turn extended by higher-order logic and type theory. First-order logic quantifies only variables that range over individuals...

arguments, sets and their elements, vectors, spaces, etc. In mathematical logic, a variable is a symbol that either represents an unspecified constant of the...

In logic, a quantifier is an operator that specifies how many individuals in the domain of discourse satisfy an open formula. For instance, the universal...

are interesting in the context of logics such as two-variable logic with counting that restrict the number of variables in formulas. Also, generalized counting...

Logic Complexity Navigator for examples). Many DLs are decidable fragments of first-order logic (FOL) and are usually fragments of two-variable logic...

All of these types of variables can be quantified. There are two kinds of interpretations commonly employed for higher-order logic. Full semantics require...

Combinatory logic is a notation to eliminate the need for quantified variables in mathematical logic. It was introduced by Moses Schönfinkel and Haskell...

Fuzzy logic is a form of many-valued logic in which the truth value of variables may be any real number between 0 and 1. It is employed to handle the concept...

mathematical logic and computer science, a variable may be said to be either free or bound. Some older books use the terms real variable and apparent variable for...

In logic, temporal logic is any system of rules and symbolism for representing, and reasoning about, propositions qualified in terms of time (for example...

In logic, a metavariable (also metalinguistic variable or syntactical variable) is a symbol or symbol string which belongs to a metalanguage and stands...

can even wrap beyond the edge of the chart for variable minimization. This is because each logic variable corresponds to each vertical column and horizontal...

propositional logic, ψ is a substitution instance of φ if and only if ψ may be obtained from φ by substituting formulas for propositional variables in φ, replacing...

logic, algebraic logic is the reasoning obtained by manipulating equations with free variables. What is now usually called classical algebraic logic focuses...

In digital logic, an inverter or NOT gate is a logic gate which implements logical negation. It outputs a bit opposite of the bit that is put into it...

first-order logic. In those contexts, a formula is a string of symbols φ for which it makes sense to ask "is φ true?", once any free variables in φ have...

Microsoft and Oracle. Metavariable (logic) xyzzy Alice and Bob John Doe Fnord Free variables and bound variables Gadget Lorem ipsum Nonce word Placeholder...

mathematical logic, Boolean algebra is a branch of algebra. It differs from elementary algebra in two ways. First, the values of the variables are the truth...

In mathematical logic, a ground term of a formal system is a term that does not contain any variables. Similarly, a ground formula is a formula that does...

In mathematics and logic, plural quantification is the theory that an individual variable x may take on plural, as well as singular, values. As well as...

of deriving conclusions from premises. They are integral parts of formal logic, serving as norms of the logical structure of valid arguments. If an argument...

stratification. Schematic variables in first-order logic are usually trivially eliminable in second-order logic, because a schematic variable is often a placeholder...

In logic, more specifically proof theory, a Hilbert system, sometimes called Hilbert calculus, Hilbert-style system, Hilbert-style proof system, Hilbert-style...

branch of logic. It is also called propositional logic, statement logic, sentential calculus, sentential logic, or sometimes zeroth-order logic. Sometimes...

Classical logic Computability logic Deontic logic Dependence logic Description logic Deviant logic Doxastic logic Epistemic logic First-order logic Formal...

features, like logical variables and backtracking. Today most Prolog implementations include one or more libraries for constraint logic programming. The difference...