Monomorphism from Total Ordering
From ProofWiki
Theorem
Let the following conditions hold:
- $(1): \quad$ Let $\left({S, \circ, \preceq}\right)$ and $\left({T, *, \preccurlyeq}\right)$ be ordered semigroups.
- $(2): \quad$ Let $\phi: S \to T$ be a mapping.
- $(3): \quad$ Let $\preceq$ be a total ordering on $S$.
Then $\phi \left({S, \circ, \preceq}\right) \to \left({T, *, \preccurlyeq}\right)$ is a (structure) monomorphism iff:
- $(1): \quad \phi$ is strictly increasing from $\left({S, \preceq}\right)$ into $\left({T, \preccurlyeq}\right)$;
- $(2): \quad \phi$ is a homomorphism from $\left({S, \circ}\right)$ into $\left({T, *}\right)$.
Proof
This follows:
- $(1): \quad$ As a direct consequence of Order Monomorphism iff Strictly Increasing;
- $(2): \quad$ From the definition of monomorphism as a homomorphism which is an injection.
$\blacksquare$
Sources
- Seth Warner: Modern Algebra (1965)... (previous)... (next): $\S 15$: Theorem $15.4$