Definition:Subtraction

Natural Numbers
Let $$\mathbb{N}$$ be the set of natural numbers.

Let $$m, n \in \mathbb{N}$$ such that $$m \le n$$. Then we define the symbol "$$-$$" thus:

$$\mathbf {Define:} \ n - m = p \ \stackrel {\mathbf {def}} {==} \ m + p = n$$

This is a translation of the definition Unique Minus in the naturally ordered semigroup.