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Sebathon's user avatar
Sebathon's user avatar
Sebathon
  • Member for 6 years, 8 months
  • Last seen this week
  • Santiago, Chile
5 votes

Applications and uses for the Lebesgue number of a open cover

5 votes
Accepted

Possibility of a Gauss Bonnet theorem for the total mean curvature

5 votes
Accepted

Evaluate $ \int_{-1}^1 \frac{1}{x}dx$.

3 votes
Accepted

For $x,y,z \in \mathbb{R}^n$ is it true that $\max\{|x_i-z_i|\} \leq \max\{|x_i-y_i|\} + \max\{|y_i-z_i|\}$ for $1 \leq i \leq n$?

3 votes
Accepted

Questions about the Zeta function in Stein's complex analysis

3 votes

Is it true that a smooth, harmonic functions with compactly supported gradient is trivial?

3 votes
Accepted

Inverse Fourier transform of $e^{-\alpha |\xi|^2} \hat{f}(x)$

3 votes
Accepted

All Hilbert spaces are isometric to $l^2(E)$ - how?

2 votes
Accepted

Derivative of a composite function $h = f\circ g$ where $f\colon \mathbb{R}^2\to \mathbb{R}$

2 votes
Accepted

$L^2$-norm of sum smaller than $L^2$-norm of either summand

2 votes

Continuity problem - bounding $|f(x)|\leq|x|$

2 votes
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Diffeomorphism maps interval into interval in monotone way

2 votes
Accepted

The proof differentiability of multilinear function using "product" of function.

2 votes

Ricci curvature and Bochner identity

2 votes
Accepted

Schauder basis in $L^2([0,1] \times [0,1], \mathbb{R}^2)$

2 votes

Brezis book, Functional analysis, Sobolev spaces and PDE, problem 8.30

2 votes
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Proof of first step theorem 7.7.1. in Lars Hormander's "The Analysis of Linear Partial Differential Operators I"

2 votes
Accepted

Using interpolation in Sobolev Space

2 votes
Accepted

Prove that $f$ where $|f(z)| \leq |f(\frac{z}{2})| + \frac{1}{2^n} $ is a constant function.

2 votes

How is the harmonic map related to the second fundamental form?

1 vote
Accepted

About Leray-Schauder fixed point theorem’s application in PDE

1 vote

Reference request for Isoperimetric Inequality using Sobolev inequality

1 vote

Riesz's representation of a k-current

1 vote

Showing that the space of Hilbert-Schmidt operators form a Banach space.

1 vote

Proof of isoperimetric inequality in $\mathbb R^n$

1 vote
Accepted

Sobolev embedding implies lowerbound on the volumn of the ball

1 vote

I don't understand the proof that $ \| \overline{u} \|_{W^{1,p}(B)} \leq C \| u \|_{W^{1,p}(B^+)}$

1 vote

Would you recommend me a text book reference?

1 vote
Accepted

Show that the coordinates of $X = (d\phi)(\tilde{X})$ are $ X^i = \sum_{j}\frac{\partial u^i}{\partial \tilde{u}^j} \tilde{X}^j. $

1 vote
Accepted

Finding the limit of an integral over a finite measure set