Union of Power Sets is Power Set of unions.
95800
Prove that if $\mathcal P(A) \cup \mathcal P(B)= \mathcal P(A\cup B)$ then either $A \subseteq B$ or $B \subseteq A$.
11849
Size of a union of two sets
117658
A set with n elements has 2^n subsets
37951
proof detail concerning bijection between a set and its power set
93952
Show that $X$ can be represented as a union of disjoint equivalence classes
46240
Show that if $A$ and $B$ are sets, then $(A\cap B) \cup (A\cap \overline{B})=A$.
9082
Do sets, whose power sets have the same cardinality, have the same cardinality?
155999
How to prove the following properties of infimum and supremum involving the union and intersection of the sets $A_k$
100726
Prove that the set of powers of a set, $\{ A^n : n \in \mathbb{N} \}$ exists by using ZFC axioms (without replacement).
23442
Cardinality of the union of infinite and countable sets
139155
What does 2 to the power x mean in set theory
104550
Countable union of countable sets(ZF)
147213
Prove that finite unions of compact sets are compact
47602
Convergence of Sets? (Topology on a Powerset of a Set?)
89506
Union of disjoint sets : Equivalence relations
146664
The union of two linearly independent subsets
26530
What does the big intersection or union sign of a set mean?