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visits member for 3 years, 11 months
seen Oct 20 at 18:15

Jan
27
revised If A $\subset S^n$ has spherical diameter < $\pi$, then $S^n - A$ contains a closed semisphere.
corrected question
Jan
25
asked If A $\subset S^n$ has spherical diameter < $\pi$, then $S^n - A$ contains a closed semisphere.
Dec
19
comment Distinction between 'adjoint' and 'formal adjoint'
These lines on Wikipedia only describe the construction for a differential operator. I have been concerned about general operators and their formal adjoints.
Nov
16
awarded  Yearling
Nov
8
asked Correct term for trivial extension of linear operator on Hilbert spaces
Nov
2
comment Solid angle between vectors in n-dimensional space
Your second formula is quite awkward, because you apply arctan against a vector.
Oct
27
accepted Is the Empty set an orientable manifold?
Oct
27
asked Is the Empty set an orientable manifold?
Jul
28
awarded  Popular Question
Jul
19
revised Bound the pseudo-inverse matrix of a product
Typo
Jul
18
comment Proof by Induction $n^2+n$ is even
You know you don't need induction, do you?
Jul
18
asked Bound the pseudo-inverse matrix of a product
Jul
11
comment Minimizer of $p$-average of distances to points $x_1,\dots,x_n$
@ChristianBlatter: A name, like some exotic mean, would be helpful, of course.
Jul
11
comment Minimizer of $p$-average of distances to points $x_1,\dots,x_n$
@Paul: Yes, by definition. The vector $D$ is just a formal device.
Jul
11
asked Minimizer of $p$-average of distances to points $x_1,\dots,x_n$
Jul
7
answered How to use Galerkin approximation to find the existence of weak solution.
Jul
6
accepted The Betti numbers of a triangulated ball relative to a disk in its boundary
Jul
6
revised The Betti numbers of a triangulated ball relative to a disk in its boundary
clarification
Jul
6
asked The Betti numbers of a triangulated ball relative to a disk in its boundary
Jun
20
asked Slobodeckij and Bessel definitions of fractional Sobolev spaces on Lipschitz domains