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Student
  • Member for 12 years, 11 months
  • Last seen more than 1 year ago
31 votes
5 answers
126k views

Check my proof that $(ab)^{-1} = b^{-1} a^{-1}$

18 votes
4 answers
3k views

Proofs that involve Tricks

18 votes
1 answer
14k views

Interior of a convex set is convex [duplicate]

15 votes
5 answers
3k views

Prove that $(a_1a_2\cdots a_n)^{2} = e$ in a finite Abelian group

12 votes
2 answers
1k views

Recalling Proofs

10 votes
3 answers
3k views

Rudin Theorem $1.11$

10 votes
1 answer
5k views

The Product of Subgroups of an Abelian Group

9 votes
7 answers
7k views

Group Multiplication Table

9 votes
2 answers
8k views

An infinite subset of a countable set is countable

7 votes
2 answers
8k views

Monotonic function only has jump discontinuities

6 votes
3 answers
6k views

Not a Zero Divisor

6 votes
3 answers
6k views

Intersection of a closed set and compact set is compact [duplicate]

6 votes
3 answers
8k views

Center of a Group

6 votes
3 answers
2k views

Subgroup of a Finite Group

5 votes
3 answers
4k views

Orbit vs. Cycle

5 votes
1 answer
535 views

When a Permutation is not a cycle

5 votes
2 answers
2k views

In a group, the number of non-self-inverse elements is even

5 votes
2 answers
6k views

Order of Cyclic Subgroups

5 votes
3 answers
6k views

Closure and limit of a sequence

5 votes
1 answer
7k views

Degrees of Freedom of a Unitary Matrix Proof

4 votes
0 answers
5k views

Showing the Unit Circle is Connected

4 votes
1 answer
2k views

Sequence of Polynomials and Weierstrass's Approximation Theorem

4 votes
3 answers
5k views

Continuity defined for rational and irrational numbers

4 votes
1 answer
135 views

How to understand $\delta$ and $\varepsilon$ in real analysis?

4 votes
2 answers
417 views

Why is a Borel algebra a $\sigma$-algebra?

4 votes
3 answers
10k views

A set $E$ is closed if and only if $E = E^-$

4 votes
2 answers
1k views

Rudin Theorem 2.30

4 votes
1 answer
2k views

Is this proof that if $a_{n+1} = \sqrt{2 + \sqrt{a_n}}$ and $a_1 = \sqrt{2}$, then $\sqrt{2} \leq a_n \leq 2$ correct?

4 votes
2 answers
626 views

Cauchy by Definition

4 votes
3 answers
444 views

Double Subsequences