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612 votes

6 answers

83k views

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general-topology algebraic-topology

Chris

6,123

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257 votes

40 answers

30k views

Fun but serious mathematics books to gift advanced undergraduates.

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162 votes

1 answer

7k views

What properties of busy beaver numbers are computable?

computability

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137 votes

6 answers

8k views

Why does mathematical convention deal so ineptly with multisets?

notation terminology math-history multisets

MJD

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82 votes

1 answer

7k views

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real-analysis number-theory irrational-numbers geometric-construction

lhf

209k

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79 votes

3 answers

5k views

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number-theory prime-numbers modular-arithmetic congruences random

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68 votes

10 answers

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Is memory unimportant in doing mathematics?

soft-question learning

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65 votes

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4k views

When is an infinite product of natural numbers regularizable?

sequences-and-series reference-request divergent-series products regularization

Timmy Turner

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41 votes

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calculus probability integration probability-theory geometric-probability

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38 votes

4 answers

3k views

Why is it considered unlikely that there could be a contradiction in ZF/ZFC?

soft-question set-theory meta-math

user23211

asked Feb 22, 2012 at 1:37

35 votes

12 answers

8k views

Is this a valid proof that there are infinitely many natural numbers?

elementary-set-theory proof-explanation

groov

439

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33 votes

2 answers

762 views

Placing the integers $\{1,2,\ldots,n\}$ on a circle ( for $n>1$) in some special order

combinatorics number-theory

user228168

asked Jan 8, 2016 at 1:51

32 votes

3 answers

3k views

Proof of recursive formula for "fusible numbers"

elementary-number-theory recreational-mathematics

Alon Amit

15k

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32 votes

1 answer

964 views

Are sines of primes dense in $[-1,1]?$

real-analysis prime-numbers

user23211

asked Feb 15, 2012 at 22:29

28 votes

1 answer

1k views

FO-definability of the integers in (Q, +, <)

logic model-theory

Michaël Cadilhac

1,004

asked May 21, 2011 at 22:34

28 votes

1 answer

649 views

Power towers: to infinity and all the way back

real-analysis sequences-and-series limits asymptotics logarithms

Լ.Ƭ.

1,034

asked Aug 13, 2013 at 19:23

25 votes

1 answer

6k views

A proof of Wolstenholme's theorem

number-theory binomial-coefficients alternative-proof

joriki

217k

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21 votes

2 answers

400 views

A strangely connected subset of $\Bbb R^2$

geometry metric-spaces

MJD

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21 votes

2 answers

7k views

What's the difference between hyperreal and surreal numbers?

field-theory number-systems nonstandard-analysis surreal-numbers

Nathan Reed

897

asked Oct 26, 2012 at 4:30

20 votes

1 answer

738 views

Short intervals with all numbers having the same number of prime factors

number-theory prime-numbers

Dan Brumleve

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19 votes

2 answers

4k views

Integration analog of automatic differentiation

calculus integration

Mikhail

772

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17 votes

3 answers

783 views

How, if at all, does pure mathematics benefit from $2^{74207281}-1$ being prime?

number-theory discrete-mathematics reference-request prime-numbers recreational-mathematics

Damian Reding

8,633

asked Jan 21, 2016 at 22:50

16 votes

1 answer

2k views

Does the "prime ant" ever backtrack?

combinatorics asymptotics random-walk oeis

Peter Kagey

4,928

asked Oct 24, 2017 at 6:32

16 votes

4 answers

582 views

Graph Isomorphism for non-mathematician

graph-theory soft-question

Jakub Konieczny

12.1k

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15 votes

1 answer

919 views

Is this condition sufficient to ensure monotonicity of a function?

calculus real-analysis analysis

Nick Strehlke

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14 votes

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1k views

Can multiplication be defined in terms of divisibility?

number-theory logic arithmetic

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number-theory prime-numbers

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Infinitely many polygons, no four have a common point

geometry discrete-geometry

jack

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12 votes

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Biggest Little Polyhedron

geometry polyhedra open-problem extremal-combinatorics combinatorial-geometry

Ed Pegg

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12 votes

4 answers

4k views

Does DTIME(O(n)) = REGULAR?

computer-science computational-complexity

templatetypedef

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Why can you turn clothing right-side-out?

Fun but serious mathematics books to gift advanced undergraduates.

What properties of busy beaver numbers are computable?

Why does mathematical convention deal so ineptly with multisets?

Direct proof that $\pi$ is not constructible

Mathematicians shocked(?) to find pattern in prime numbers

Is memory unimportant in doing mathematics?

When is an infinite product of natural numbers regularizable?

Rain droplets falling on a table

Why is it considered unlikely that there could be a contradiction in ZF/ZFC?

Is this a valid proof that there are infinitely many natural numbers?

Placing the integers $\{1,2,\ldots,n\}$ on a circle ( for $n>1$) in some special order

Proof of recursive formula for "fusible numbers"

Are sines of primes dense in $[-1,1]?$

FO-definability of the integers in (Q, +, <)

Power towers: to infinity and all the way back

A proof of Wolstenholme's theorem

A strangely connected subset of $\Bbb R^2$

What's the difference between hyperreal and surreal numbers?

Short intervals with all numbers having the same number of prime factors

Integration analog of automatic differentiation

How, if at all, does pure mathematics benefit from $2^{74207281}-1$ being prime?

Does the "prime ant" ever backtrack?

Graph Isomorphism for non-mathematician

Is this condition sufficient to ensure monotonicity of a function?

Can multiplication be defined in terms of divisibility?

Smallest prime in arithmetic progressions: upper bounds?

Infinitely many polygons, no four have a common point

Biggest Little Polyhedron

Does DTIME(O(n)) = REGULAR?