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388
Answers
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75
Not especially famous, long-open problems which anyone can understand
Jun 22 '12 at 6:39
70
Why were matrix determinants once such a big deal?
Sep 22 '10 at 10:29
38
Is square of Delta function defined somewhere?
Dec 3 '10 at 10:30
36
Old books still used
Dec 28 '12 at 17:22
36
Why are matrices ubiquitous but hypermatrices rare?
Dec 2 '10 at 14:50
29
Examples of common false beliefs in mathematics
Oct 19 '10 at 15:51
28
Mathematical “urban legends”
Apr 7 '11 at 9:36
27
How often do people read the work that they cite?
Jun 5 '12 at 7:58
27
Is the boundary $\partial S$ analogous to a derivative?
Mar 30 '11 at 20:28
25
John Nash's Mathematical Legacy
May 24 '15 at 16:45
25
how to find/define eigenvectors as a continuous function of matrix?
Dec 12 '12 at 7:30
22
German mathematical terms like “Nullstellensatz”
Apr 19 '11 at 9:07
21
Awfully sophisticated proof for simple facts
Oct 17 '10 at 19:07
19
A sum involving derivatives of Vandermonde
Oct 19 '11 at 7:10
18
Self-dual normed spaces which are not Hilbert spaces
Mar 15 '12 at 21:01
18
Where is number theory used in the rest of mathematics?
Mar 9 '12 at 16:02
18
Is the Mendeleev table explained in quantum mechanics?
Nov 5 '11 at 21:18
18
Mathematical “urban legends”
Feb 1 '11 at 12:03
17
Eigenvalues of non-symmetric matrix and its transpose
May 23 '12 at 11:12
16
2D Problems Which are Easier to Solve in 3D
Sep 9 '12 at 6:32
16
Theorems that are 'obvious' but hard to prove
Jan 9 '11 at 13:46
16
Generalized notions of solutions in various areas of mathematics
Oct 7 '10 at 13:42
16
Why do we teach calculus students the derivative as a limit?
Sep 27 '10 at 7:15
15
Facts from algebraic geometry that are useful to non-algebraic geometers
Sep 16 '10 at 15:35
14
Does any research mathematics involve solving functional equations?
Jan 27 '11 at 7:23
14
submultiplicity of matrix norm. Is $||AB||_F \leq ||A||_2||B||_F$?
Mar 29 '11 at 6:32
14
Example of sequences with different limits for two norms
Feb 1 '11 at 12:47
13
Pfaffian equals complex determinant?
Apr 19 at 10:10
13
Eigenvectors and eigenvalues of Tridiagonal matrix
Mar 14 '12 at 12:08
13
Why is differentiating mechanics and integration art?
May 30 '11 at 9:40
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