Assuming a finite domain, such a formula can be unrolled into a conjunction of propositional statements of the form F ij = r s (e i , e j ) ⇒ r t (e i , e j ), one for each entity-pair (e i , e j ) in the domain.
[F] = (e i ,e j )∈P [F ij ], and therefore L([F]) = (e i ,e j )∈P L([F ij ]).