# Definition:Additive Inverse/Ring

< Definition:Additive Inverse(Redirected from Definition:Additive Inverse in Ring)

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*This page is about Additive Inverse of Ring. For other uses, see Additive Inverse.*

## Definition

Let $\struct {R, +, \circ}$ be a ring whose ring addition operation is $+$.

Let $a \in R$ be any arbitrary element of $R$.

The **additive inverse** of $a$ is its inverse under ring addition, denoted $-a$:

- $a + \paren {-a} = 0_R$

where $0_R$ is the zero of $R$.

### Additive Inverse of Number

The concept is often encountered in the context of numbers:

Let $\Bbb F$ be one of the standard number systems: $\N$, $\Z$, $\Q$, $\R$, $\C$.

Let $a \in \Bbb F$ be any arbitrary number.

The **additive inverse** of $a$ is its inverse under addition, denoted $-a$:

- $a + \paren {-a} = 0$

## Sources

- 1989: Ephraim J. Borowski and Jonathan M. Borwein:
*Dictionary of Mathematics*... (previous) ... (next): Entry:**additive inverse**(in a ring or group)