# Logic Symbols

A comprehensive collection of the most notable symbols in formal/mathematical logic, categorized by function into tables along with each symbol's meaning and example.

In philosophy and mathematics, logic plays a key role in formalizing valid deductive inferences and other forms of reasoning. The following is a comprehensive list of the most notable symbols in logic, featuring symbols from propositional logic, predicate logic, Boolean logic and modal logic.

For readability purpose, these symbols are categorized by their function into tables. Other comprehensive lists of symbols — as categorized by subject and type — can be also found in the relevant pages below (or in the navigational panel).

Get the master summary of mathematical symbols in eBook form — along with each symbol’s usage and LaTeX code.

## Constants

In logic, constants are often used to denote definite objects in a logical system. The following table features the most notable of these — along with their respective example and meaning.

## Variables

Similar to other fields in mathematics, variables are used as placeholder symbols for varying entities in logic. The following table documents the most notable of these — along with their respective example and meaning.

## Operators

Operators are symbols used to denote mathematical operations, which serve to take one or multiple inputs to a similar output. In logic, these operators include logical connectives from propositional/modal logic, quantifiers from predicate logic, as well as other operators related to syntactic substitution and semantic valuation.

## Relational Symbols

In logic, relational symbols play a key role in turning one or multiple mathematical entities into formulas and propositions, and can occur both within a logical system or outside of it (as metalogical symbols). The following table documents the most notable of these symbols — along with their respective meaning and example.

For the master list of symbols, see mathematical symbols. For lists of symbols categorized by type and subject, refer to the relevant pages below for more.