538 reputation
212
bio website
location
age
visits member for 3 years, 6 months
seen 14 hours ago

Jul
18
accepted Distortion and Norm Stabilization
Jul
18
comment Distortion and Norm Stabilization
Nice answer! The "trick" I did not see was your first inequality; everything follows from it. I think that it is important to note that when you prove that the existence of a distortable subspace $Y$ gives you a non-stabilizing equivalent norm $\lvert \cdot \rvert$, we are implicity using the fact that we can extend $\lvert \cdot \rvert$ from $Y$ to an equivalent norm on $X$ (since, by definition, we need this norm to be defined on the whole space, not just on $Y$).
Jul
17
revised Distortion and Norm Stabilization
added 6 characters in body
Jul
17
revised Distortion and Norm Stabilization
added 1 character in body
Jul
17
comment Distortion and Norm Stabilization
@ChristopherA.Wong: We say that $X$ is distortable if it is $\lambda$-distortable for some $\lambda > 1$.
Jul
17
revised Distortion and Norm Stabilization
added 131 characters in body
Jul
17
asked Distortion and Norm Stabilization
Jul
2
awarded  Curious
Jun
5
accepted Correlation Sequences and Unitary Operators
Jun
5
comment Correlation Sequences and Unitary Operators
It came up during a lecture on Fourier Analysis, right before proving Wiener Theorem. I guess it was supposed to be "trivial".
Jun
5
comment Correlation Sequences and Unitary Operators
Never mind, I understand it now.
Jun
4
comment Correlation Sequences and Unitary Operators
How do you know that Wiener's Theorem implies $\frac1N\sum_{n=1}^N|c_n|^2\xrightarrow[N\to\infty]{}0$? I mean, it seems that you're assuming that $\mu$ is continuous.
Jun
4
revised Correlation Sequences and Unitary Operators
edited title
Jun
4
revised Correlation Sequences and Unitary Operators
added 1 character in body
Jun
3
comment Correlation Sequences and Unitary Operators
Is really close. However, my question is about convergence in $\mathbb{R}$, not in $H$ (as in the Mean Ergodic Theorem). I still don't see how to approach this problem...
Jun
3
revised Correlation Sequences and Unitary Operators
edited tags
Jun
3
asked Correlation Sequences and Unitary Operators
Jun
3
accepted Eigenvectors of a Multiplication Operator
Jun
3
asked Eigenvectors of a Multiplication Operator
Apr
23
awarded  Tumbleweed