Strictly Monotone Mapping with Totally Ordered Domain is Injective

Let $$\left({S; \le_1}\right)$$ be a totally ordered set.

Let $$\left({T; \le_2}\right)$$ be a poset.

Let $$\phi: \left({S; \le_1}\right) \to \left({T; \le_2}\right)$$ be a mapping which is strictly monotone.

Then $$\phi$$ is injective.

Proof
Hence the result.