Search Results
| Search type | Search syntax |
|---|---|
| Tags | [tag] |
| Exact | "words here" |
| Author |
user:1234 user:me (yours) |
| Score |
score:3 (3+) score:0 (none) |
| Answers |
answers:3 (3+) answers:0 (none) isaccepted:yes hasaccepted:no inquestion:1234 |
| Views | views:250 |
| Code | code:"if (foo != bar)" |
| Sections |
title:apples body:"apples oranges" |
| URL | url:"*.example.com" |
| Saves | in:saves |
| Status |
closed:yes duplicate:no migrated:no wiki:no |
| Types |
is:question is:answer |
| Exclude |
-[tag] -apples |
| For more details on advanced search visit our help page | |
Results tagged with fourier-analysis
Search options not deleted
user 153260
The representation of functions (or objects which are in some generalize the notion of function) as constant linear combinations of sines and cosines at integer multiples of a given frequency, as Fourier transforms or as Fourier integrals.
4
votes
1
answer
432
views
Reference or proof of a theorem of L. Fejér on summability of Fourier series
In the article "Ensembles exceptionnels" by A. Beurling, the author cites the following theorem of Fejér:
Suppose that a $2\pi$ periodic function $ f $, Lebesgue integrable in $(0,2\pi)$ satisfies the …
1
vote
Fourier series but different waveform
Partial answer: About linear independence, it is true that if $f$ is non constant then the dilations $f_n(x)=f(nx), n\in \mathbb{N}$ are linearly independent. In fact suppose for a finite sum we hav …
8
votes
A curious norm related to the L¹ norm
I think $C=2$ is the best constant. Consider $\varepsilon>0$ and let $f,g$ continuous in $[0,1]$ defined as follows.
\begin{equation*}
f(x) = \begin{cases} -1, & 0\leq x \leq \frac12 - \varepsilon \\
…
2
votes
Operator norm of some type of discrete Fourier matrix
You can use the $F_wF_w^*$ argument to calculate the operator norm of the matrix. In fact we have that the elements of $ F_w $ are of the form $f_{kn} = \lambda^k_n $.
So the entries of $F_wF_w^*$ are …