Constant Operation is Commutative

Theorem
Let $$S$$ be a set.

Let $$x \left[{c}\right] y = c$$ be a constant operation on $$S$$.

Then $$\left[{c}\right]$$ is a commutative operation:

$$\forall x, y \in S: x \left[{c}\right] y = y \left[{c}\right] x$$