In: Advanced Math
Definition 2.3.2 in our book defines the power set of a set S, denoted by P(S), as the set of all subsets of S, that is P(S) = {A : A ⊆ S}. For example, P({1, 2}) = {∅, {1}, {2}, {1, 2}}, and P(∅) = {∅}. Consider the relation ⊆ on the power set P(Z), i.e. the is-a-subset-of relation defined on sets of integers. In other words, the objects we compare are sets of integers. (a) Prove or disprove: ⊆ is reflexive. (b) Prove or disprove: ⊆ is irreflexive. (c) Prove or disprove: ⊆ is symmetric. (d) Prove or disprove: ⊆ is antisymmetric. (e) Prove or disprove: ⊆ is transitive. (f) Is ⊆ on Z an equivalence relation? Is it a partial order? (g) Which other relation satisfies exactly the same properties?