User Thibaut Demaerel

9 votes

1 answer

169 views

Characterization of a sphere: sub-spheres have two (antipodal) centers?

differential-geometry riemannian-geometry

asked Dec 27, 2017 at 10:18

7 votes

1 answer

134 views

binomial identity: elementary proof possible?

asked Dec 13, 2019 at 15:16

7 votes

2 answers

336 views

Can orthogonal matrix with positive diagonal have -1 in its spectrum?

linear-algebra inequality orthogonal-matrices

asked Jul 21, 2021 at 14:46

5 votes

2 answers

671 views

Hyperplanes and convex sets in Hilbert space

functional-analysis convex-analysis hahn-banach-theorem

asked Feb 22, 2019 at 13:01

5 votes

0 answers

193 views

What is the minimal area of a fully-fledged Dyson sphere?

euclidean-geometry recreational-mathematics problem-solving

asked Jul 21, 2019 at 11:42

5 votes

1 answer

126 views

A version of Casorati-Weierstrass for harmonic functions?

harmonic-functions

asked Jan 27, 2016 at 17:41

4 votes

0 answers

115 views

Does infinite mikado exist?

probability geometry euclidean-geometry recreational-mathematics packing-problem

asked Aug 8, 2018 at 15:24

4 votes

2 answers

364 views

Minimal conditions to ensure uniqueness of solutions of Schrödinger equation IVP

functional-analysis reference-request partial-differential-equations mathematical-physics

asked Feb 16, 2019 at 23:55

3 votes

1 answer

45 views

Two harmonic functions with positive ratio are multiple of each-other?

harmonic-functions

asked Mar 6, 2021 at 13:09

3 votes

1 answer

48 views

Is the complement of a set with vanishing $(d-2)-$dimensional Hausdorff measure simply connected?

reference-request differential-topology fundamental-groups geometric-measure-theory

asked May 16 at 16:24

2 votes

1 answer

77 views

Finite Coulomb energy implies potential level sets enclose finite volume?

integration functional-analysis fourier-analysis mathematical-physics

asked Mar 1 at 14:34

2 votes

1 answer

93 views

Connecting n keys to n safes in minimal number of attempts

combinatorics computational-complexity

asked Apr 21, 2019 at 17:00

2 votes

0 answers

66 views

A question about 'onions' in $\varepsilon$-nets on 2-dim manifolds

differential-geometry metric-spaces meshing

asked Sep 7, 2021 at 17:19

2 votes

0 answers

47 views

Fokker-Planck counterpart of Grönwall inequality/comparison theorem

partial-differential-equations reference-request stochastic-processes stochastic-calculus heat-equation

asked Jan 7, 2020 at 15:59

2 votes

1 answer

289 views

Mazur's lemma without Hahn-Banach theorem/axiom of choice?

functional-analysis convex-analysis weak-convergence gradient-descent gradient-flows

asked Feb 20, 2019 at 15:22

2 votes

1 answer

63 views

Identifying a theorem (or class of theorems) in commutative algebra

linear-algebra combinatorics reference-request commutative-algebra

asked Dec 23, 2017 at 14:42

2 votes

2 answers

113 views

Riemann integration: usefulness of partitions

real-analysis integration measure-theory riemann-integration

asked Nov 10, 2019 at 20:30

2 votes

0 answers

97 views

A kind of Sturm-Picone theorem?

ordinary-differential-equations dynamical-systems sturm-liouville

asked Feb 7, 2016 at 21:25

2 votes

0 answers

55 views

Inequality involving periodic functions

real-analysis inequality periodic-functions

asked Jul 22, 2017 at 17:42

2 votes

1 answer

108 views

only solution to wave equation under certain restriction?

partial-differential-equations wave-equation

asked Dec 22, 2014 at 18:19

2 votes

1 answer

60 views

nontrivial 'sub' Banach spaces

functional-analysis banach-spaces

asked Sep 8, 2015 at 10:36

2 votes

2 answers

140 views

Vectorfields satisfying SO(3) algebra 2 dimensional?

differential-geometry lie-algebras

asked Nov 7, 2015 at 14:46

1 vote

0 answers

46 views

"Scattering" in Riemannian spaces.

geometry differential-geometry riemannian-geometry

asked Jan 13, 2016 at 17:41

1 vote

1 answer

385 views

Linear maps preserving the determinant and Hermiticity

proof-verification linear-transformations alternative-proof multilinear-algebra

asked Oct 11, 2015 at 8:23

1 vote

1 answer

80 views

(non)existence certain smooth function of compact support.

calculus real-analysis ordinary-differential-equations

asked Mar 16, 2015 at 17:56

1 vote

1 answer

97 views

almost unital Banach algebra's

operator-algebras banach-algebras

asked Mar 21, 2015 at 14:03

1 vote

1 answer

75 views

spectral theory expandable to arbitrary polynomials?

functional-analysis operator-theory banach-spaces operator-algebras spectral-theory

asked Apr 3, 2015 at 16:45

1 vote

0 answers

26 views

How does one call/characterise sewn-together Riemannian manifolds

geometry reference-request terminology riemannian-geometry mathematical-physics

asked Aug 13, 2018 at 17:32

1 vote

1 answer

33 views

perfect lens: expression for interface

real-analysis geometry ordinary-differential-equations closed-form applications

asked Dec 4, 2019 at 13:23

1 vote

0 answers

127 views

Parseval's theorem for the Hankel transform

functional-analysis fourier-analysis

asked Mar 11, 2019 at 13:50

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42 Questions

Characterization of a sphere: sub-spheres have two (antipodal) centers?

binomial identity: elementary proof possible?

Can orthogonal matrix with positive diagonal have -1 in its spectrum?

Hyperplanes and convex sets in Hilbert space

What is the minimal area of a fully-fledged Dyson sphere?

A version of Casorati-Weierstrass for harmonic functions?

Does infinite mikado exist?

Minimal conditions to ensure uniqueness of solutions of Schrödinger equation IVP

Two harmonic functions with positive ratio are multiple of each-other?

Is the complement of a set with vanishing $(d-2)-$dimensional Hausdorff measure simply connected?

Finite Coulomb energy implies potential level sets enclose finite volume?

Connecting n keys to n safes in minimal number of attempts

A question about 'onions' in $\varepsilon$-nets on 2-dim manifolds

Fokker-Planck counterpart of Grönwall inequality/comparison theorem

Mazur's lemma without Hahn-Banach theorem/axiom of choice?

Identifying a theorem (or class of theorems) in commutative algebra

Riemann integration: usefulness of partitions

A kind of Sturm-Picone theorem?

Inequality involving periodic functions

only solution to wave equation under certain restriction?

nontrivial 'sub' Banach spaces

Vectorfields satisfying SO(3) algebra 2 dimensional?

"Scattering" in Riemannian spaces.

Linear maps preserving the determinant and Hermiticity

(non)existence certain smooth function of compact support.

almost unital Banach algebra's

spectral theory expandable to arbitrary polynomials?

How does one call/characterise sewn-together Riemannian manifolds

perfect lens: expression for interface

Parseval's theorem for the Hankel transform