User Cristi Stoica

138 votes

17 answers

22k views

What makes four dimensions special?

asked Nov 28, 2010 at 8:51

80 votes

25 answers

14k views

Examples of non-rigorous but efficient mathematical methods in physics

asked Dec 8, 2010 at 20:30

39 votes

9 answers

3k views

A series of articles should be published all in the same journal, or in different journals?

asked May 17, 2011 at 7:22

20 votes

5 answers

2k views

How and how much do the notations and diagrams influence our understanding of mathematical concepts?

asked Oct 23, 2010 at 11:21

19 votes

2 answers

8k views

Conditions for smooth dependence of the eigenvalues and eigenvectors of a matrix on a set of parameters

asked Oct 22, 2010 at 4:29

17 votes

5 answers

2k views

Can always a family of symmetric real matrices depending smoothly on a real parameter be diagonalized by smooth similarity transformations?

asked Apr 4, 2011 at 9:16

16 votes

3 answers

2k views

Applications of visual calculus

asked May 12, 2013 at 8:34

15 votes

1 answer

2k views

Interpolating between piecewise linear functions, with a family of smooth functions

asked Aug 18, 2011 at 8:50

14 votes

5 answers

2k views

Singular semi-Riemannian Geometry: usefulness and state of the art

asked Dec 1, 2010 at 9:56

12 votes

2 answers

2k views

Factorization of a matrix as a product of a symmetric and a skew-symmetric matrix

asked Nov 25, 2015 at 21:39

7 votes

1 answer

291 views

Can a tangle of arcs interlock in plane?

asked Aug 27, 2013 at 14:47

7 votes

3 answers

1k views

Open problems in sub-Riemannian geometry

asked Aug 12, 2012 at 19:16

6 votes

1 answer

2k views

Classification of smooth atlases

asked Feb 17, 2012 at 15:55

6 votes

3 answers

3k views

Can the adjoint of the exterior derivative in semi-Riemannian geometry be defined without the Hodge * operator?

asked Oct 16, 2010 at 7:44

6 votes

0 answers

595 views

Properties that are between intrinsic and extrinsic in Riemannian geometry

asked Aug 30, 2017 at 17:45

5 votes

1 answer

538 views

Cosets of groups of functions

asked Feb 18, 2012 at 7:50

5 votes

1 answer

367 views

Homogeneous metrics of given volume element, on the n-sphere.

asked Jul 23, 2012 at 14:39

5 votes

1 answer

383 views

Spin and SO groups associated to a degenerate symmetric bilinear form

asked Jul 31, 2012 at 20:56

3 votes

0 answers

362 views

Obtaining the metric from the mixed Ricci tensor $R^i{}_j$

asked Nov 26, 2015 at 19:45

1 vote

1 answer

171 views

If a function is defined in terms of a solution to an initial value problem, is it also solution to an initial value problem?

asked May 27, 2013 at 17:28

0 votes

3 answers

924 views

Analyticity of the solutions of PDE

asked Aug 14, 2012 at 8:05

0 votes

1 answer

1k views

Applications of the natural bilinear forms on the direct sum between a vector space and its dual

asked Feb 28, 2013 at 11:13

0 votes

1 answer

576 views

Is there something like the Hodge decomposition if the metric is indefinite?

asked May 7, 2011 at 14:46

Stack Exchange Network

24 Questions

What makes four dimensions special?

More open problems [closed]

Examples of non-rigorous but efficient mathematical methods in physics

A series of articles should be published all in the same journal, or in different journals?

How and how much do the notations and diagrams influence our understanding of mathematical concepts?

Conditions for smooth dependence of the eigenvalues and eigenvectors of a matrix on a set of parameters

Can always a family of symmetric real matrices depending smoothly on a real parameter be diagonalized by smooth similarity transformations?

Applications of visual calculus

Interpolating between piecewise linear functions, with a family of smooth functions

Singular semi-Riemannian Geometry: usefulness and state of the art

Factorization of a matrix as a product of a symmetric and a skew-symmetric matrix

Can a tangle of arcs interlock in plane?

Open problems in sub-Riemannian geometry

Classification of smooth atlases

Can the adjoint of the exterior derivative in semi-Riemannian geometry be defined without the Hodge * operator?

Properties that are between intrinsic and extrinsic in Riemannian geometry

Cosets of groups of functions

Homogeneous metrics of given volume element, on the n-sphere.

Spin and SO groups associated to a degenerate symmetric bilinear form

Obtaining the metric from the mixed Ricci tensor $R^i{}_j$

If a function is defined in terms of a solution to an initial value problem, is it also solution to an initial value problem?

Analyticity of the solutions of PDE

Applications of the natural bilinear forms on the direct sum between a vector space and its dual

Is there something like the Hodge decomposition if the metric is indefinite?