# What symbol is used for linear operator actions?

1. May 2, 2012

### sunjin09

Given a vector v$\in H$: R2->R3 which is a function from R2 to R3, and an operator G: H->H on the space H in which v lives, what is the most commonly used symbol to refer to this mapping, i.e., G(v)=G$\otimes v$ or something else?

2. May 2, 2012

### mathman

G(v) is fine.

3. May 2, 2012

### sunjin09

Thank you for replying, but I want to emphasize that G is a 3x3 matrix valued operator that multiplies the 3x1 vector valued function v then integrated over the entire domain, is the tensor product $\otimes$ appropriate? I used a dot but was complained about by the reviewer.

4. May 2, 2012

### micromass

Staff Emeritus
The tensor product is not appropriate, neither is the dot. Using G(v) makes most sense. Is there a reason why you don't want to use G(v)?

5. May 3, 2012

### sunjin09

Thanks again for clarifying, I guess I just wanted to emphasize the matrix vector multiplication part, I'll use G(v) so that there's no ambiguity. One more question though, if I apply G n times to v, n>=0, is $G^n(v)$ appropriate?

6. May 3, 2012

### sunjin09

I found the notation G^n(v)=G(G(G...G(v)...)) in a textbook. Thank you both!