This document summarizes three key points: 1) It proves the logical equivalences of three expressions: (a) ¬ (p∨ (q∨¬r)) ∧q≡ ((¬p ∧ q) ∧ R), (b) (p→r) ∨ (q→r) ≡ (p∧q) →r, and (c) (∀×∈⋃ (P(x) →¬Q(x)) ≡ ¬∃×∈⋃. (P(x) ∧Q(x)). 2) It analyzes several expressions involving predicates like D(x