User Asaf Shachar

28 votes

3 answers

2k views

Does isometric immersion map boundary to boundary?

asked Nov 4, 2016 at 14:54

26 votes

1 answer

1k views

Finding the closest matrix to $\text{SO}_n$ with a given determinant

asked Aug 11, 2017 at 16:10

25 votes

2 answers

1k views

Is there a smooth manifold which admits only rigid metrics?

asked Apr 18, 2016 at 17:23

25 votes

1 answer

2k views

Is it possible for a metric on a smooth manifold to be smooth?

asked Aug 19, 2015 at 15:17

23 votes

1 answer

706 views

Which ordered fields are homeomorphic to their power?

asked Nov 29, 2014 at 11:48

22 votes

0 answers

2k views

Characterising critical points of $E(f)=\int_{M}| \bigwedge^2 df|^2 \text{Vol}_{M}$

asked Jun 16, 2017 at 13:50

21 votes

1 answer

1k views

A differentiable isometry is smooth?

asked Feb 12, 2017 at 22:14

21 votes

1 answer

2k views

Differential Topology over $\mathbb{Q}$

asked May 21, 2015 at 13:25

20 votes

5 answers

2k views

Smoothness of the closest point on a submanifold

asked Jun 12, 2016 at 15:20

17 votes

1 answer

1k views

How many values determine a norm?

asked Apr 12, 2015 at 8:31

17 votes

1 answer

650 views

An explicit reconstruction of a matrix from its minors

asked Jun 25, 2018 at 13:55

16 votes

1 answer

1k views

Is there an area-preserving diffeomorphism of the disk which is nowhere conformal?

asked Mar 8, 2020 at 11:39

16 votes

2 answers

967 views

Tweetable way to see Riemannian isometries are harmonic?

asked Feb 14, 2017 at 8:48

15 votes

1 answer

1k views

Is $\delta(df \wedge df)=0$ an Euler-Lagrange equation?

asked May 27, 2017 at 13:20

14 votes

2 answers

506 views

Do curvature differences obstruct a.e orientation-preserving isometries?

asked Mar 17, 2017 at 9:23

14 votes

3 answers

3k views

When a homeomorphism is a diffeomorphism w.r.t to a suitable smooth structure?

asked Apr 27, 2015 at 10:53

14 votes

2 answers

1k views

Obstructions for a group to be the multiplicative group of a field [duplicate]

asked Apr 28, 2015 at 11:12

14 votes

0 answers

632 views

Are harmonic mappings non-singular outside a set of measure zero?

asked May 13, 2016 at 11:19

14 votes

2 answers

871 views

Are all maps $\mathbb{R}^2 \to \mathbb{R}^2$ with fixed singular values affine?

asked Jan 30, 2020 at 15:38

13 votes

3 answers

986 views

A conformal map whose Jacobian vanishes at a point is constant?

asked Aug 12, 2018 at 14:43

13 votes

3 answers

2k views

Is there a global obstruction for a diffeomorphism to be an isometry?

asked Apr 19, 2015 at 16:06

13 votes

1 answer

739 views

Is this expression for the Laplacian of conformal maps between Riemannian manifolds known?

asked Apr 27, 2017 at 6:14

12 votes

1 answer

415 views

Is the image of the map $A \to \bigwedge^k A$ closed over $\mathbb{R}$?

asked Jun 5, 2018 at 11:10

12 votes

2 answers

969 views

which norms can be realized as operator norms?

asked Jun 4, 2015 at 10:01

12 votes

2 answers

779 views

A Converse to Cartan–Hadamard theorem?

asked Jan 11, 2016 at 10:59

12 votes

2 answers

977 views

Are conformal maps between Riemannian manifolds real-analytic?

asked Oct 22, 2018 at 12:41

12 votes

2 answers

697 views

Is the square root of a monotonic function whose all derivatives vanish smooth?

asked May 10, 2020 at 6:43

11 votes

1 answer

565 views

Is there a "formula" for the point in $\text{SO}(n)$ which is closest to a given matrix?

asked Mar 26, 2019 at 9:02

11 votes

1 answer

3k views

Does pullback in the category of smooth manifolds always exists?

asked Oct 7, 2015 at 10:10

11 votes

1 answer

725 views

Strong equivalence between intrinsic and extrinsic metrics on $GL_n^+$?

asked Oct 29, 2015 at 18:30

Stack Exchange Network

153 Questions

Does isometric immersion map boundary to boundary?

Finding the closest matrix to $\text{SO}_n$ with a given determinant

Is there a smooth manifold which admits only rigid metrics?

Is it possible for a metric on a smooth manifold to be smooth?

Which ordered fields are homeomorphic to their power?

Characterising critical points of $E(f)=\int_{M}| \bigwedge^2 df|^2 \text{Vol}_{M}$

A differentiable isometry is smooth?

Differential Topology over $\mathbb{Q}$

Smoothness of the closest point on a submanifold

How many values determine a norm?

An explicit reconstruction of a matrix from its minors

Is there an area-preserving diffeomorphism of the disk which is nowhere conformal?

Tweetable way to see Riemannian isometries are harmonic?

Is $\delta(df \wedge df)=0$ an Euler-Lagrange equation?

Do curvature differences obstruct a.e orientation-preserving isometries?

When a homeomorphism is a diffeomorphism w.r.t to a suitable smooth structure?

Obstructions for a group to be the multiplicative group of a field [duplicate]

Are harmonic mappings non-singular outside a set of measure zero?

Are all maps $\mathbb{R}^2 \to \mathbb{R}^2$ with fixed singular values affine?

A conformal map whose Jacobian vanishes at a point is constant?

Is there a global obstruction for a diffeomorphism to be an isometry?

Is this expression for the Laplacian of conformal maps between Riemannian manifolds known?

Is the image of the map $A \to \bigwedge^k A$ closed over $\mathbb{R}$?

which norms can be realized as operator norms?

A Converse to Cartan–Hadamard theorem?

Are conformal maps between Riemannian manifolds real-analytic?

Is the square root of a monotonic function whose all derivatives vanish smooth?

Is there a "formula" for the point in $\text{SO}(n)$ which is closest to a given matrix?

Does pullback in the category of smooth manifolds always exists?

Strong equivalence between intrinsic and extrinsic metrics on $GL_n^+$?