How would we symbolize the following English sentence logically? Only a knight can marry my daughter. [ K(x): x is a knight; M(x, y): x can marry y; d: my daughter ] I have tried to create some equivalences and identities, but none of them seem to be correct.

$M(x, d) \implies K(x)$.

If $x$ marries $d$ then $x$ is a Knight.

You can throw in some quantifiers if it will make you feel better.