Complex sentence: This establishes a bijection (up to isomorphism) between the class of all finite posets and the class of all finite distributive lattices, which can in fact be extended to an equivalence of categories between finite distributive lattices and lattice homomorphisms and finite posets with monotone functions.
Split into simpler sentences: This establishes a bijection (up to isomorphism) between the class of all finite posets and the class of all finite distributive lattices. This bijection can be extended to an equivalence of categories between finite distributive lattices and lattice homomorphisms and finite posets with monotone functions.