Parity Addition is Associative/Proof 1

Theorem
Let $R := \left({\left\{ {\text{even}, \text{odd} }\right\}, +, \times}\right)$ be the parity ring.

The operation $+$ is associative:


 * $\forall a, b, c \in R: \left({a + b}\right) + c = a + \left({b + c}\right)$

Proof
From Isomorphism between Ring of Integers Modulo 2 and Parity Ring:
 * $\left({\left\{ {\text{even}, \text{odd} }\right\}, +, \times}\right)$ is isomorphic with $\left({\Z_2, +_2, \times_2}\right)$

the ring of integers modulo $2$.

The result follows from:
 * Modulo Addition is Associative

and:
 * Isomorphism Preserves Associativity.