@article{Łyczak_Pietruszczak_2018, title={On the Definability of Leśniewski’s Copula ‘is’ in Some Ontology-Like Theories}, volume={47}, url={https://czasopisma.uni.lodz.pl/bulletin/article/view/4776}, DOI={10.18778/0138-0680.47.4.02}, abstractNote={<p>We formulate a certain subtheory of Ishimoto’s [1] quantifier-free fragment of Leśniewski’s ontology, and show that Ishimoto’s theory can be reconstructed in it. Using an epimorphism theorem we prove that our theory is complete with respect to a suitable set-theoretic interpretation. Furthermore, we introduce the name constant 1 (which corresponds to the universal name ‘object’) and we prove its adequacy with respect to the set-theoretic interpretation (again using an epimorphism theorem). Ishimoto’s theory enriched by the constant 1 is also reconstructed in our formalism with into which 1 has been introduced. Finally we examine for both our theories their quantifier extensions and their connections with Leśniewski’s classical quantified ontology.</p>}, number={4}, journal={Bulletin of the Section of Logic}, author={Łyczak, Marcin and Pietruszczak, Andrzej}, year={2018}, month={Dec.}, pages={233–263} }