Skip to main content
1 of 12
Mirar
  • 350
  • 1
  • 7

Equivariant action of convolution of directional derivative

I have asked this question a while back in stackexchange but have not received any answer/comment. I received a suggestion to post the question here which is more research oriented.

Let $k*f(x)=\int_{}^{}k(x,t)f(x-t)dt$, where $x,t\in \mathbb{R}^{3}$, $f:\mathbb{R}^{3}\to\mathbb{R^{+}}$ and $k:\mathbb{R}^{3}\to\mathbb{R^{+}}$ for a given $t$. Additionally, let $v(x):\mathbb{R}^{3}\to\mathbb{R}^{3}$ and $D_{v(x)}(f(x))$ as directional derivative of $f(x)$ along $v(x)$. Is it possible to write $k*D_{v}(f)$ as a function of $k*f$:

$k*D_{v}(f)=F(k*f)$,

where $k*D_{v}(f)=\int{}^{}k(x,t)v(x-t)\nabla^{T}f(x-t)dt.$ Or is there any map/operator $F$ that generates $k*D_{v}(f)$ by acting on $k*f$ ?

Note1: Unfortunately I do not have enough reputation to add an image here. The image can be found in stackexchange. Sorry about that.

Note2: In my problem, $f$ is unknown but $k$, $v$ and $k*f$ are known numerically. Therefore, in addition to $k*f$, the map $F$ can be dependent to $k$ and/or $v$ and/or $k*v$ and/or their derivatives but there should not be any dependency to $f$ or its derivatives.

Note3: I am not a mathematician, please forgive my ignorance if I misused the terms here.

Mirar
  • 350
  • 1
  • 7