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2d
comment What are some applications of elementary linear algebra outside of math?
That's neat but actually a fake application. No image codec ever used the SVD of the full images. Back in the days when digital images were just a few hundred pixels wide computer were to slow to be practical and nowadays images are too large to perform a SVD on them. And anyway, JPEG(2000) and PNG are just way better.
2d
comment Radius of convergence, prove that $\sum\limits_{n=0}^{\infty} a_n z^n$ converges absolutely for every $z \in \mathbb{C}$ with $|z| < R$
$\rho = R - \epsilon/2$ is between $R-\epsilon$ and $R$…
2d
answered Is ${\mathbb R}^n$ with the product topology the same as the metric topology
2d
comment The equality case of the Schwartz inequality
Probably the book was "The Cauchy-Schwarz hy-schwarz master class".
2d
reviewed Reject Is there an inverse operation of tetration for values between 0 and .3?
2d
reviewed Approve Infinite product of probability measures is a premeasure
Dec
18
comment Dimension of rectifiable curve
I would prefer if you ask questions in the question format and not come up with follow up questions in comments. Take a minute and think about the question you are really interested in.
Dec
18
comment Replacing Singular Values of a Matrix with Complex Ones
Sure, multiple by $i$.
Dec
18
comment Replacing Singular Values of a Matrix with Complex Ones
The singular values of a matrix are, by definition, real and non-negative. So you'll not find a matrix with complex singular values anyway…
Dec
18
answered Dimension of rectifiable curve
Dec
18
comment Dimension of rectifiable curve
What @Martín-BlasPérezPinilla was saying is that the claim you state in the OP (one-dim Hausdorff measure of the the intersection of a rectifiable curve and a closed subset of the real line is zero) is in general false, so you'll not find a proof. But it seems that you are in a different situation…
Dec
16
reviewed Close How to solve $\sin(\arctan((\frac{1}{2}))$
Dec
16
reviewed Leave Open Can there be a bijection between a countably infinite set and an uncountably infinite set?
Dec
16
reviewed Leave Open Sum of square of absolute values of roots of a polynomial
Dec
16
reviewed Leave Open if $f'(x) = -8xe^{x^2}$ and $f(0)=3$ then $f(x) =$?
Dec
14
comment Genius mathematicians who never published anything
Wikipedia usually lists a few and perhaps the most relevant papers and often do not even include any papers. To get some ideas of the paper output one needs to check primary sources. I checked MathSciNet and he has 16 entries. His (short) list of coauthors is impressive and he has published in top notch journals.
Dec
13
answered Proving that median of list $[x_1,x_2,…,x_n]$ minimises the sum $\sum_{i=1}^{i=n} |x_i-m|$ where $m$ is some number
Dec
12
comment Genius mathematicians who never published anything
I generally dislike the idea of "mathematical geniuses". Great ideas from great people come from hard work in all cases...
Dec
12
comment Genius mathematicians who never published anything
"Hardly published anything" is not quite right. I don't have access to MathSciNet now but on Google Scholar I found more than 10 published by Perelman (also with well known coauthors). I guess his total paper count is about 20.
Dec
11
reviewed Leave Closed How to find out whether a group is Abelian