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Top Questions
25 votes

Inner product on $C(\mathbb R)$

linear-algebra functional-analysis inner-product-space axiom-of-choice asked May 30, 2014 at 11:18
math.stackexchange.com

20 votes

Prime number snake (2)

mathematics grid-deduction primes asked Jan 26, 2020 at 19:31
puzzling.stackexchange.com

10 votes

Are functions satisfying $|f(x)-f(y)|\le L \|\nabla f(x)-\nabla f(y)\|^{1+s}$ constant?

real-analysis asked Dec 11, 2018 at 8:56
math.stackexchange.com

8 votes

Sparsest matrix with full inverse

linear-algebra matrices recreational-mathematics asked Jul 3, 2014 at 16:47
math.stackexchange.com

7 votes

Upper bound on $\sum_{n=1}^\infty q^{(n^2)}$

real-analysis sequences-and-series power-series asked Jul 10, 2018 at 8:43
math.stackexchange.com

7 votes

Proof of Linear independence of generalized eigenvectors without applying generalized eigenspace decomposition.

linear-algebra eigenvalues-eigenvectors asked Jun 26, 2014 at 8:16
math.stackexchange.com

7 votes

Is a sign-preserving operator on $L^2$ a multiplication?

fa.functional-analysis operator-theory lattice-theory asked Jul 29, 2019 at 7:15
mathoverflow.net

7 votes

Can the space of linear operators on a Hilbert space be made into a Hilbert space?

functional-analysis operator-theory hilbert-spaces asked Nov 2, 2022 at 8:57
math.stackexchange.com

6 votes

Caratheodory's theorem with two vectors

geometry convex-analysis convex-geometry polytopes convex-hulls asked Oct 30, 2021 at 11:07
math.stackexchange.com

5 votes

$L^p$ estimates for linear parabolic pdes

ap.analysis-of-pdes sobolev-spaces parabolic-pde asked Mar 16, 2022 at 19:02
mathoverflow.net

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Top Answers
22
Is every Hilbert space separable?
math.stackexchange.com

19
Orthogonal Projection of $ z $ onto the Affine set $ \left\{ x \mid A x = b \right\} $
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19
What's in my pocket?
puzzling.stackexchange.com

18
How can you compute in your head?
puzzling.stackexchange.com

17
Is KKT conditions necessary and sufficient for any convex problems?
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17
Knights attacking exactly three knights
puzzling.stackexchange.com

14
Ensuring that a symmetric matrix with nonnegative elements is positive semidefinite
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13
How to show that $A^2=AB+BA$ implies $\det(AB-BA)=0$ for $3\times3$ matrices?
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12
Using the Bolzano's theorem to prove that exists only one solution in the interval.
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12
Proof of Linear independence of generalized eigenvectors without applying generalized eigenspace decomposition.
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11
Proving or disproving matrix $A+B$ is invertible
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11
Queens attacking exactly four queens
puzzling.stackexchange.com

11
Union of closed convex sets
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10
Eigenvectors and eigenvalues from $X^TX$ to $XX^T$?
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10
Kronecker product and matrix multiplication property
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10
Prove set $\left\{(x,y)\in\mathbb R^{2} : \frac{x^2}{4}+\frac{y^2}{9}<1\right\}$ is open
math.stackexchange.com

9
Alice, Bob and Charlie know the sum, product and the difference between two numbers
puzzling.stackexchange.com

9
On Equivalent Norms in an Infinite Dimensional Vector Space
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8
No minimal polynomial for differentiation operator
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8
Is $ \{A\in \mathbb{R}^{n,n}: 0<\det(A)<2\} $ compact?
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8
How convexity is related with weak lower semi continuity?
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8
Rank of transformation $Y=AX-XA$
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8
Projection of a point onto a simple convex polytope
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8
How to show a space is not reflexive?
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8
Show a bounded linear operator is weakly sequentially continuous
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8
How to show that this bounded linear operator is onto?
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8
Spectrum of Multiplication Operator $T$ in $C[0,1]$
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7
$T$ is surjective if and only if the adjoint $T^*$ is an isomorphism (onto its image)
math.stackexchange.com

7
Setka - Complete grid using clues and sudoku-style logic; Theme - Halftime
puzzling.stackexchange.com

7
Proving if A and B are matrices such that A, B, and AB are normal, then BA is also normal.
math.stackexchange.com

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