Jan Łukasiewicz (1878–1956) was co-founder of the Warsaw School of Logic.
In the Spring of 1964 Sobocinski taught a course dealing with Lesniewski's Ontology. Items 1 and 2 below are the first part of that course.
While in Brussels, Sobocinski prepared three notebooks dealing with Ontology. Item 5 below is the third of them. The first two will be added later after I scan them.
When Lesniewski pubished O podstawach matematyki (On the foundations of mathematics; briefly OPM) he was uncomfortable with formal language and so expressed these derivations in ordinary (Polish) language. Here Sobocinski has translated them into the formal language of Mereology.
Item 1 is the first development of Mereolgy, Item 2 is the second.
Item 1 is the list of Sobocinski's papers that Rickey prepared when donating about half of his papers to the Archives at the University of Notre Dame. Item 2 is the arrangement of the papers that was prepared by the archivists.