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John Doe's user avatar
John Doe's user avatar
John Doe
  • Member for 9 years, 9 months
  • Last seen more than a month ago
70 votes
13 answers
15k views

What is the definition of a set?

69 votes
11 answers
4k views

Why is it not true that $\int_0^{\pi} \sin(x)\; dx = 0$?

40 votes
8 answers
53k views

What is the difference between partial and normal derivatives?

32 votes
1 answer
5k views

Question about distributive law in definition of a ring

28 votes
3 answers
42k views

Structure of groups of order $pq$, where $p,q$ are distinct primes. [duplicate]

24 votes
4 answers
7k views

Are all Lie groups Matrix Lie groups?

21 votes
5 answers
31k views

Proving that all integers are even or odd [duplicate]

20 votes
5 answers
1k views

Finding the derivative of function with domain empty set

18 votes
2 answers
2k views

How are simple groups the building blocks?

15 votes
2 answers
6k views

Order of the Rubik's cube group

13 votes
6 answers
7k views

When are two series the same?

12 votes
2 answers
6k views

Are ideals also rings?

12 votes
2 answers
2k views

When is a class function the character of a representation?

10 votes
3 answers
1k views

Do I understand the difference between $\implies$ and $\to$? [duplicate]

10 votes
3 answers
4k views

Precise definition of free group

10 votes
7 answers
3k views

Is $\sqrt{x}$ an even function?

9 votes
4 answers
2k views

Representation theory of $\mathbb{R}$?

9 votes
2 answers
548 views

Proving that $SL_2(\mathbb{Z}_5) / \{\pm I\}\simeq A_5$

8 votes
1 answer
12k views

Why are logarithms of trigonometric functions useful?

8 votes
5 answers
2k views

Is the trivial ring a subring?

8 votes
2 answers
8k views

When is $HK$ a subgroup?

7 votes
2 answers
2k views

An $n$ degree polynomial with more than $n$ roots?

7 votes
5 answers
262 views

Going from completion to explicit description of the real numbers

7 votes
2 answers
2k views

Group of automorphisms of $(\mathbb{R}, +)$

7 votes
3 answers
3k views

What does echelon mean?

7 votes
6 answers
7k views

Continuity and limits at end point of interval

6 votes
6 answers
213 views

Calculating $\int \sqrt{1 + x^{-2}}dx$

6 votes
2 answers
1k views

Showing that $\lvert H K\rvert = \frac{| H\| K|}{ |H\cap K|}$ [duplicate]

6 votes
1 answer
1k views

How do you integrate a $0$-form?

6 votes
4 answers
421 views

Are all groups algebraic?

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