Showing this set is an algebra
120273
Showing that a collection of sets is a $\sigma$-algebra: either set or complement is countable
2575
Showing that $\mathbb{R}$ is connected
118595
Proving that a set is countable by finding a bijection
38946
Show that $\{\cup_{n\in K} (n, n+1]: K \subset \mathbb{Z}\}$ is a $\sigma$-algebra on $\mathbb{R}$
37119
Determine Which of the following Sets is a Vector Space
51094
Prove that the set of integer coefficients polynomials is countable
98577
Show that the set $\mathbb{Q}(\sqrt{p})=\{a+b\sqrt{p}; a,b,p\in\mathbb{Q},\sqrt{p}\notin \mathbb{Q}\}$ is a field
104274
Express $C$ interms of the sets $A_n$
144502
Showing that $A\cap B = A\setminus (A\setminus B)$
21820
How to prove that a set is invariant?
77791
Proving an inclusion related to algebraic sets and interpreting it
89234
Any Set with Associativity, Left Identity, Left Inverse is a Group
34998
How to prove that $\mathbb{Q}$ ( the rationals) is a countable set
86263
How do we show there are the same number of elements in each of the sets?
52135
Show that $A \setminus ( B \setminus C ) \equiv ( A \setminus B) \cup ( A \cap C )$
96152
Showing that $a^n - 1 \mid a^m - 1 \iff n \mid m$
90584
Show set of affine transformations is a group