Is $ (A∪B)×(C∩D)=(A×C)∪(B×D)$ true for all sets A,B,C and D?
66563
Is $ (A∪B)×(C∩D)=(A∪C)×(B∪D)$ true for all sets A,B,C and D?
11168
Proof of divisibility: if $a|b$ and $a|(b+c)$ then $a|c$
71976
Is every element on a set also a set?
68258
Let $A,B,C$ be sets, and $B \cap C=\emptyset$. Show $|A^{B \cup C}|=|A^B \times A^C|$
120495
Does this correctly interpret the "$\cong$" between groups as "$=$" between sets?
2208
$\gcd(a,b,c)=\gcd(\gcd(a,b),c)\,$ [GCD Associative Law]
13136
Element chasing proof that $(A\setminus C)\setminus(B\setminus C) = (A\setminus B)\setminus C$
104274
Express $C$ interms of the sets $A_n$
63535
Prove that if $A – C = B – C$ and $A\cap C = B\cap C$ then $A = B$
89506
Union of disjoint sets : Equivalence relations
150738
Proof of $(A - B) - C = A - (B \cup C)$
144360
For any sets $A$ and $B$, show that $(B\smallsetminus A)\cup A=B \iff A\subseteq B$.
41080
If A, B, and C are set and $A \subset B ,B \subset C \rightarrow A \subset C$
79568
Cardinality of the set $D$
137626
If $a,b,c$ are positive integers,and $\cfrac{a}{b}+\cfrac{b}{c}+\cfrac{c}{a}$ and $\cfrac{b}{a}+\cfrac{c}{b}+\cfrac{a}{c}$ are integers then $a=b=c$
104068
Prove that $\forall a,b\in\mathbb{C} \exists c,d \in \mathbb{C}: c+d = a \land cd = b$
33633
Re:$ (a,b,c,d)=(pr+qs, qr-ps,pr-qs,ps+qr) $