Proving a union of sets
127720
Prove that $\bigcup_{n \in \Bbb{N}} [1/n,1] = (0,1]$.
86263
How do we show there are the same number of elements in each of the sets?
88628
Proving the total number of subsets of S is equal to $2^n$
30231
The boundary of union is the union of boundaries when the sets have disjoint closures
77286
Proving set theory question
113083
How to prove a set equality?
109070
Question about the proof of the distributive property for sets
80156
Formatting the union of sets
24685
Expressing a Countable Union of Sets as the Countable Union of Disjoint Sets (e.g. Eliminating Duplicate Intersections)
99464
Proof Concerning Indexed family of Sets and Intervals
144360
For any sets $A$ and $B$, show that $(B\smallsetminus A)\cup A=B \iff A\subseteq B$.
116527
Validating a proof for necessary and sufficient conditions on sets A & B such that $P(A) \cup P(B) = P(A\cup B)$
140044
A set union find algorithm
50880
Expressing $\Bbb N$ as an infinite union of disjoint infinite subsets.
111032
Proof of Sets involving the Cartesian Product
137707
How to prove that $(A\cup B) \cap C \subseteq A\cup (B\cap C)$
10180
How to prove that this set is closed?