Negative of Ring Negative

Theorem
Let $\left({R, +, \circ}\right)$ be a ring.

Let $a \in R$ and let $-a$ be the ring negative $-a$ of $a$.

Then $- \left({-a}\right) = a$.

Proof
The ring negative is, by definition of a ring, the inverse element of $a$ in the additive group $\left({R, +}\right)$.

The result then follows from Inverse of an Inverse.