Skip to main content
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
Search options not deleted user 10583

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.

2 votes

Continuous or analytic functions with this property of sinc function

In fact, the identity is true for the function $f(x)=\frac{\sin ax}{ax}$ for each $0\lt a\le \pi$. For the integral part, just apply substitution. For the series part, use the fact that $\sum_{n=1}^ …
TCL's user avatar
  • 744
3 votes
7 answers
1k views

Continuous or analytic functions with this property of sinc function

This question is motivated by my previous post in SE (math.stackexchange.com). Prove or disprove that $\frac{\sin x}{x}$ is the only nonzero entire (i.e. analytic everywhere), or continuous, function …
TCL's user avatar
  • 744
2 votes
Accepted

Characterizations of a linear subspace associated with Fourier series

This is to summarize what were discussed in the comments, so the title will not be listed as unanswered. The linear subspace $S$ of $c_0(\mathbb{Z})$ is equal to the convolution product of two copies …
TCL's user avatar
  • 744
4 votes
1 answer
2k views

Characterizations of a linear subspace associated with Fourier series

Let $c_0$ be the Banach space of doubly infinite sequences $$\lbrace a_n: -\infty\lt n\lt \infty, \lim_{|n|\to \infty} a_n=0 \rbrace.$$ Let $T$ be the space of $2\pi$ periodic functions integrable …
TCL's user avatar
  • 744