In
mathematics,
equality is a relationship between two quantities or, more generally two
mathematical expressions, asserting that the quantities have the same value, or that the expressions represent the same
mathematical object. The equality between
A and
B is written
A =
B, and pronounced
A equals
B. The symbol "=" is called an "
equals sign". Thus there are three kinds of equality, which are formalized in different ways.
- Two symbols refer to the same object.
- Two sets have the same elements.
- Two expressions evaluate to the same value, such as a number, vector, function or set.
These may be thought of as the logical, set-theoretic and algebraic concepts of equality respectively.