User Igor Khavkine

79 votes

Proofs without words

answered Dec 16, 2009 at 11:32

49 votes

John Nash's Mathematical Legacy

answered May 24, 2015 at 18:26

43 votes

Accepted

Is there a closed form for $\int_0^\infty\frac{\tanh^3(x)}{x^2}dx$?

answered Jun 7, 2017 at 18:27

39 votes

Accepted

Is there any way to rewrite a partial differential equation using language of differential forms, tensors, etc?

answered May 23, 2013 at 12:26

33 votes

Accepted

Style of mathematical writing vs. too many lemmas

answered Jun 16, 2015 at 20:02

32 votes

Accepted

How much of mathematical General Relativity depends on the Axiom of Choice?

answered Aug 21, 2023 at 0:45

30 votes

Accepted

How to prove Lambert's W function is not elementary?

answered Jul 6, 2013 at 10:47

30 votes

Accepted

The speed of gravitational waves in general relativity

answered Nov 10, 2012 at 22:34

29 votes

An example of a beautiful proof that would be accessible at the high school level?

answered Sep 8, 2011 at 11:37

28 votes

Can infinity shorten proofs a lot?

answered Feb 1, 2012 at 14:56

22 votes

Accepted

Which differential equations allow for a variational formulation?

answered Jul 6, 2012 at 10:16

21 votes

The concept of duality

answered Aug 26, 2011 at 11:05

21 votes

What is an "Instanton" in classical gauge theory? (to a mathematician)

answered Dec 30, 2017 at 10:26

21 votes

Atlas-like websites on specific areas of mathematics

answered Mar 6, 2020 at 19:08

21 votes

Accepted

Does anyone recognize this condition on a Riemannian metric on a vector space?

answered Feb 9 at 1:49

20 votes

No canonical isomorphism

answered Apr 22, 2021 at 22:28

18 votes

Is there a relation between 4-dimensional general relativity and exotic smooth structures on $\mathbb{R}^4$?

answered Sep 20, 2011 at 23:58

16 votes

Mathematical explanation of the failure to quantize gravity naively

answered Jan 28, 2010 at 16:53

14 votes

Topology on the set of analytic functions

answered Aug 28, 2013 at 16:13

14 votes

Obtain Lorentzian manifolds from Riemannian ones by Wick rotation

answered May 6, 2014 at 14:02

14 votes

Accepted

soft: Reference/ Suggested Read: Homological Algebraic techniques in PDEs

answered Aug 1, 2015 at 20:28

13 votes

Accepted

$A \wedge A \wedge A$ in Chern-Simons

answered May 27, 2015 at 10:40

13 votes

Accepted

Mathematical foundations of Quantum Field Theory

answered Apr 15, 2012 at 15:22

12 votes

Hodge decomposition in Minkowski space

answered Jun 6, 2013 at 12:06

12 votes

Accepted

Boundary terms of formal adjoints of differential operators

answered Dec 22, 2017 at 17:04

11 votes

Accepted

What are the necessary and sufficient conditions for a two-form to be an exterior product of two one-forms?

answered Dec 17, 2018 at 11:39

11 votes

Formal mathematical definition of renormalization group flow

answered Aug 5, 2019 at 15:45

11 votes

Why the least action principle is always (?) used in this particular form?

answered Sep 26, 2020 at 10:10

11 votes

The open problem in General Relativity?

answered Apr 4, 2015 at 20:40

11 votes

Accepted

"Cohomology at the infinity": what does one call it

answered May 7, 2013 at 21:53

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371 Answers

Proofs without words

John Nash's Mathematical Legacy

Is there a closed form for $\int_0^\infty\frac{\tanh^3(x)}{x^2}dx$?

Is there any way to rewrite a partial differential equation using language of differential forms, tensors, etc?

Style of mathematical writing vs. too many lemmas

How much of mathematical General Relativity depends on the Axiom of Choice?

How to prove Lambert's W function is not elementary?

The speed of gravitational waves in general relativity

An example of a beautiful proof that would be accessible at the high school level?

Can infinity shorten proofs a lot?

Which differential equations allow for a variational formulation?

The concept of duality

What is an "Instanton" in classical gauge theory? (to a mathematician)

Atlas-like websites on specific areas of mathematics

Does anyone recognize this condition on a Riemannian metric on a vector space?

No canonical isomorphism

Is there a relation between 4-dimensional general relativity and exotic smooth structures on $\mathbb{R}^4$?

Mathematical explanation of the failure to quantize gravity naively

Topology on the set of analytic functions

Obtain Lorentzian manifolds from Riemannian ones by Wick rotation

soft: Reference/ Suggested Read: Homological Algebraic techniques in PDEs

$A \wedge A \wedge A$ in Chern-Simons

Mathematical foundations of Quantum Field Theory

Hodge decomposition in Minkowski space

Boundary terms of formal adjoints of differential operators

What are the necessary and sufficient conditions for a two-form to be an exterior product of two one-forms?

Formal mathematical definition of renormalization group flow

Why the least action principle is always (?) used in this particular form?

The open problem in General Relativity?

"Cohomology at the infinity": what does one call it