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el_tenedor
  • Member for 8 years, 11 months
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6 votes
Accepted

Exponential of the Laplacian operator as diffusion equation

6 votes
Accepted

Prove that $T(x^* + W^{\perp}) = y^*$ is an isometric isomorphism from $V^*/W^\perp$ to $W^*$

5 votes

Calculate a determinant.

4 votes
Accepted

Determinants of $3A, -A, A^2, A^{-1}$, where A is an $4\times 4$ matrix and $\det(A) = \frac{1}{3}$?

4 votes

How Hahn-Banach theorem implies that the dual space is non-trivial?

4 votes
Accepted

Isomorphism between dual space tensor vector space and set of linear transformations

3 votes
Accepted

Uniqueness of limit point of a Cauchy Sequence

3 votes
Accepted

Positive operator on a Hilbert Space

3 votes
Accepted

Hahn-Banach and seminorms

3 votes
Accepted

(direct) sum vs span of subspaces

3 votes

What is the result of $\bigcap_{n=1}^{\infty}{(-1/n; 1/n)}$

3 votes
Accepted

simplifying the sum $\sum_{j<k} T_{jk}$ for symmetric $T$

3 votes
Accepted

Adjoint of inverse map is the inverse of adjoint map?

3 votes
Accepted

Pseudometric and metric

2 votes
Accepted

About a maximal linearly independent subset

2 votes
Accepted

Proving $\sup(A)+\sup(B)=\sup(A+B)$

2 votes
Accepted

$X$ a normed space. $(x_n) \subset X$ s.t. $|f(x_n)| < M_f$ for all $n$ and $\forall f \in X^{\ast}$ then there is $C$ s.t. $\|x_n\| \le C$

2 votes

What is the difference between dense and closed sets?

2 votes

Maclaurin series of $f(x) = e^x \sin x$

2 votes

relation between conformal and orthogonal matrices in 2D

2 votes
Accepted

Linear maps: $A,B \in L(V,W)$: if $r(A)=r(B)$ then $B=SAT$

2 votes

Determining the domain of the adjoint of $T = i\frac{d}{dx}$ on $C^1[0,1] \subseteq L^2[0,1]$

2 votes
Accepted

Metric on product of metric spaces

1 vote
Accepted

An exercise using uniform boundedness principle

1 vote
Accepted

Proof of the Cotlar–Stein almost-orthogonality lemma

1 vote

Hilbert Space: Orthogonal projection is linear

1 vote
Accepted

sequence of continuous functions on a Banach space X

1 vote

Divergence test for real series

1 vote

Definition of the space of Hölder continuous functions

1 vote
Accepted

Almost Uniform convergence Theorem (Egoroff) doubts