# Is "P=M" a well-formed predicate log formula in a domain?

A predicate $$P(x)$$ "$$x$$ is possible" and $$M(x)$$ "$$x$$ is a mission" and all in the "Possible Mission domain of disclosure."

Is $$P=M$$ a well-formed predicate logic?

I would say yes because, both the predicates are in the same domain. The question is a bit confusing for me.

Thanks

Predicates are used to form statements, while the equality symbol $$=$$ is a relation between terms : variables and (individual) constants, i.e. "names" of objects.
Thus, we may write e.g. $$x=y$$ and $$\forall x Px$$ but not $$Px=Mx$$.
$$\forall x (Mx \rightarrow Px)$$.