show/hide this revision's text 4 added 273 characters in body; edited title

Continuity of a convolution (Version 2)

Hello,

This problem bothers me for some time. Suppose that

  1. $\mu$ is a non-negative Radon measure (or positive linear functional of the space of continuous functions with compact support);
  2. $\psi$ is a continuous function, vanishing at infinity and integrable, i.e., $\psi\in C^0_0(R)\cap L^1(R)$;
  3. $\sup_{x \in R}|(\psi*\mu)(x)|<+\infty$.

Then, we would like to prove that the function $x\mapsto (\psi*\mu)(x)$ is continuous.

Thank you very much for your help and any hints!

Anand


Version 2. If we add an additional property,

  1. $\sup_{x\in R} |(G*\mu)(x)|<+\infty$, where $G(x)=\frac{1}{\sqrt{2\pi}}\exp(-x^2/2)$.

Then, is it possible to prove that the function $x\mapsto (\psi*\mu)(x)$ is continuous?

Thanks

Anand

show/hide this revision's text 3 Change Condition (2)

Hello,

This problem bothers me for some time. Suppose that

  1. $\mu$ is a non-negative Radon measure (or positive linear functional of the space of continuous functions with compact support);
  2. $\psi$ is a continuous function, vanishing at infinity and integrable, i.e., $\psi\in C^0(R)\cap C^0_0(R)\cap L^1(R)$;
  3. $\sup_{x \in R}|(\psi*\mu)(x)|<+\infty$.

Then, we would like to prove that the function $x\mapsto (\psi*\mu)(x)$ is continuous.

Thank you very much for your help and any hints!

Anand

show/hide this revision's text 2 Condition 3 has been changed

Hello,

This problem bothers me for some time. Suppose that

  1. $\mu$ is a non-negative Radon measure (or positive linear functional of the space of continuous functions with compact support);
  2. $\psi$ is a continuous function and integrable, i.e., $\psi\in C^0(R)\cap L^1(R)$;
  3. for some
  4. $x_0\in R$, $|(\psi*\mu)(x_0)|\sup_{x \in R}|(\psi*\mu)(x)|<+\infty$.

Then, we would like to prove that the function $x\mapsto (\psi*\mu)(x)$ is continuousin a neighborhood of $x_0$..

Thank you very much for your help and any hints!

Anand

show/hide this revision's text 1 [made Community Wiki]