(114) Let us consider sets A, B, C, D. Suppose i. AmissesD, and ii. BmissesD, and iii. CmissesD. Then (A∪B)∪CmissesD. (115) A⊄∅. (116) X∩(Y∩Z)=(X∩Y)∩(X∩Z). (117) Let us consider sets P, G, C. Suppose C⊆G. Then P∖C=(P∖G)∪P∩(G∖C).