User gamma

17 votes

"Stick it to the man!" Mathematical discoveries that resulted in persecution.

answered Oct 11, 2014 at 23:31

13 votes

In the surreal numbers, is it fair to say $0.9$ repeating is not equal to $1$?

answered Sep 11, 2014 at 1:05

13 votes

Accepted

An easy to understand definition of $\omega_1$?

answered Oct 13, 2014 at 17:35

10 votes

Anecdotes about famous mathematicians or physicists

answered Nov 2, 2016 at 1:51

9 votes

Accepted

Mathematics and literature

answered Oct 5, 2014 at 1:20

8 votes

Accepted

Prove that if $gcd(a, b) = c$ then $c^2|ab$.

answered Aug 8, 2013 at 20:25

6 votes

Proving $(0,1)$ and $[0,1]$ have the same cardinality

answered Nov 4, 2014 at 21:35

5 votes

Munkres Chapter 1 Section 7 Exercise 8

answered Nov 6, 2014 at 20:58

5 votes

Bijection between the reals and the set of permutations of the natural numbers?

answered Sep 5, 2014 at 20:33

4 votes

Accepted

finding divisors of every integers

answered Aug 20, 2013 at 22:56

4 votes

Examples of mathematical results discovered "late"

answered Nov 10, 2014 at 5:00

4 votes

Theorems in number theory whose first proofs were long and difficult

answered Oct 11, 2014 at 21:03

4 votes

How to prove that there are infinitely many primes without using contradiction

answered Dec 6, 2014 at 5:32

3 votes

Prove that $4$ divides $3^{2m+1} - 3$

answered Jun 18, 2016 at 20:30

3 votes

Big list of serious but fun "unusual" books

answered Oct 15, 2014 at 21:53

3 votes

Was there anybody before Cantor who conjectured existence of infinities of different sizes?

answered Nov 8, 2014 at 22:12

3 votes

Infiniteness of non-twin primes.

answered Oct 10, 2014 at 1:27

2 votes

The definition of "number"

answered Aug 7, 2013 at 20:06

2 votes

How to formulate "The $n$ smallest"

answered Sep 15, 2014 at 18:19

2 votes

Simplifying a proof by contradiction: if $a\equiv 1\bmod 5$, then $a^2\equiv 1\bmod5$

answered Sep 21, 2014 at 1:13

2 votes

Accepted

Why is a union of n countable sets countable?

answered Nov 2, 2014 at 23:43

2 votes

What is the simplest way to get Bernoulli numbers?

answered Jun 1 at 15:41

2 votes

Cardinality of set of Dedekind cuts (elementary)

answered Nov 5, 2014 at 22:17

1 vote

Accepted

How to prove that the set of all not-empty and finite subsets of $\mathbb{N}$ is countable?

answered Nov 3, 2014 at 0:28

1 vote

modular arithmetic congruence

answered Oct 13, 2014 at 23:34

1 vote

Accepted

How do you use mathematic logical notation to notate a function whose output positively correlates with the input?

answered Nov 9, 2014 at 20:58

1 vote

Mathematical Induction divisibility $8\mid 3^{2n}-1$

answered Nov 10, 2014 at 2:26

1 vote

Cardinality of infinite sets - Help with intuition

answered Nov 12, 2014 at 20:00

1 vote

$2$-element subsets of $n$ elements?

answered Oct 7, 2014 at 22:10

1 vote

Accepted

how do you know if a collection of subsets is a field?

answered Sep 13, 2014 at 3:11

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44 Answers

"Stick it to the man!" Mathematical discoveries that resulted in persecution.

In the surreal numbers, is it fair to say $0.9$ repeating is not equal to $1$?

An easy to understand definition of $\omega_1$?

Anecdotes about famous mathematicians or physicists

Mathematics and literature

Prove that if $gcd(a, b) = c$ then $c^2|ab$.

Proving $(0,1)$ and $[0,1]$ have the same cardinality

Munkres Chapter 1 Section 7 Exercise 8

Bijection between the reals and the set of permutations of the natural numbers?

finding divisors of every integers

Examples of mathematical results discovered "late"

Theorems in number theory whose first proofs were long and difficult

How to prove that there are infinitely many primes without using contradiction

Prove that $4$ divides $3^{2m+1} - 3$

Big list of serious but fun "unusual" books

Was there anybody before Cantor who conjectured existence of infinities of different sizes?

Infiniteness of non-twin primes.

The definition of "number"

How to formulate "The $n$ smallest"

Simplifying a proof by contradiction: if $a\equiv 1\bmod 5$, then $a^2\equiv 1\bmod5$

Why is a union of n countable sets countable?

What is the simplest way to get Bernoulli numbers?

Cardinality of set of Dedekind cuts (elementary)

How to prove that the set of all not-empty and finite subsets of $\mathbb{N}$ is countable?

modular arithmetic congruence

How do you use mathematic logical notation to notate a function whose output positively correlates with the input?

Mathematical Induction divisibility $8\mid 3^{2n}-1$

Cardinality of infinite sets - Help with intuition

$2$-element subsets of $n$ elements?

how do you know if a collection of subsets is a field?