Two types of ontological structure. Concepts Structures and lattices of elementary situations

In 1982, Wolniewicz proposed a formal ontology of situations based on the lattice of elementary situations (cf. [7, 8]). In [3], I constructed some types of formal structure - Porphyrian Tree Structures (PTS), Con- cepts Structures (CS) and the Structures of Individuals (U) - that formally represent ontologically fundamental categories: species and genera (PTS), concepts (CS) and individual beings (U) (cf. [3, 4]). From an ontological perspective, situations and concepts belong to different categories. But, unexpectedly, as I shall show, some variants of CS and Wolniewicz’s lattice are similar. The main theorem states that a subset of a modified concepts structure (called CS+) based on CS fulfils the axioms of Wolniewicz’ lattice. Finally, I shall draw some philosophical conclusions and state some formal facts.