# Symbolic logic

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Symbolic logic

Symbolic logic is the area of mathematics which studies the purely formal properties of strings of symbols. The interest in this area springs from two sources. First, the symbols used in symbolic logic can be seen as representing the words used in philosophical logic. Second, the rules for manipulating symbols found in symbolic logic can be implemented on a computing machine.

Symbolic logic is usually divided into two subfields, propositional logic and predicate logic. Other logics of interest include temporal logic, modal logic and fuzzy logic. See also model theory.

Modern mathematical areas arising out of formal logic are grouped under the heading mathematical logic.

Propositional logic

The area of symbolic logic called propositional logic, originally called "propositional calculus" but not to be confused with the school subject calculus, studies the properties of sentences formed from constants, usually designated A, B, C, ... and five logical operators, AND, OR, IMPLIES, EQUALS and NOT. The corresponding logical operations are known, respectively, as conjunction, disjunction, material conditional, biconditional, and negation. These five operators are sometimes denoted as keywords, especially in computer languages, and sometimes by special symbols (see Table of logic symbols). All except NOT are binary operators; NOT is a unary operator which precedes its operand. The values of these operators are given by truth tables.

Predicate logic

Predicate logic, originally called "predicate calculus", expands on propositional logic by the introduction of variables, usually denoted by "x", "y", "z", or other lowercase letters, and also by the introduction of sentences containing variables, called predicates, usually denoted by an uppercase letter followed by a list of variables, such as P("x") or Q("y","z"). In addition, predicate logic allows so-called quantifiers, representing ALL and EXISTS.

ee also

*Table of logic symbols

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• symbolic logic — n. a modern type of formal logic using special symbols for propositions, quantifiers, and relationships among propositions and concerned with the elucidation of permissible operations upon such symbols …   English World dictionary

• symbolic logic — simbolinė logika statusas T sritis fizika atitikmenys: angl. symbolic logic vok. symbolische Logik, f rus. символическая логика, f pranc. logique symbolique, f …   Fizikos terminų žodynas

• symbolic logic — noun any logical system that abstracts the form of statements away from their content in order to establish abstract criteria of consistency and validity • Syn: ↑mathematical logic, ↑formal logic • Hypernyms: ↑logic, ↑logical system, ↑system of… …   Useful english dictionary

• symbolic logic — a modern development of formal logic employing a special notation or symbolism capable of manipulation in accordance with precise rules. Also called mathematical logic. [1880 85] * * * …   Universalium

• symbolic logic — symbol′ic log′ic n. pho a modern development of formal logic employing a special notation or symbolism capable of manipulation in accordance with precise rules Also called mathematical logic …   From formal English to slang

• symbolic logic — noun Synonym for mathematical logic (obsolescent) …   Wiktionary

• symbolic logic — General term, not currently much used, for the study of formal logic . Generally, the study of logical form requires using particular schematic letters and variables (‘symbols’) to stand where terms of a particular category might occur in… …   Philosophy dictionary

• symbolic logic — /sɪmˌbɒlɪk ˈlɒdʒɪk/ (say sim.bolik lojik) noun a system of logic that has been reduced to a set of precise rules, used in mathematical proofs and also in constructing digital computers …   Australian English dictionary

• symbolic logic — noun Date: 1856 a science of developing and representing logical principles by means of a formalized system consisting of primitive symbols, combinations of these symbols, axioms, and rules of inference …   New Collegiate Dictionary

• symbolic logic — noun the use of symbols to denote propositions, terms, and relations in order to assist reasoning …   English new terms dictionary