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 harmonic-analysis
Search options not deleted
user 18698
Harmonic analysis is a generalisation of Fourier analysis that studies the properties of functions. Check out this tag for abstract harmonic analysis (on abelian locally compact groups), or Euclidean harmonic analysis (eg, Littlewood-Paley theory, singular integrals). It also covers harmonic analysis on tube domains, as well as the study of eigenvalues and eigenvectors of the Laplacian on domains, manifolds and graphs.
7
votes
Accepted
Can the Cesaro limit of a positive definite function be negative?
I hope it's not frowned upon to answer one's own question, but since I just figured out the answer it doesn't make sense to keep it unanswered and there are a few upvotes so the answer may interest ot …
- 1,701
9
votes
1
answer
332
views
Can the Cesaro limit of a positive definite function be negative?
Let $G$ be a countable amenable group and $\gamma:G\to\mathbb{C}$ a positive (semi)definite function (i.e. such that $\gamma(g^{-1})=\overline{\gamma(g)}$ and
$$\sum_{g,h\in G}f(g)\overline{f(h)}\gam …
- 1,701
2
votes
Accepted
Continuous function defined by measurable sets
The answer is yes, and the assumption of profiniteness is not needed (see comments). This can be proved by approximating in $L^2$
the indicator function $1_A$ by a continuous function $f$.
Using th …
- 1,701