# What does $<\cdot>$ notation mean in gradient?

I've seen the use of the notation $< \cdot>$ in the context of the vector gradient $\nabla f$.

What does $< \cdot >$ mean? I've also seen the use of $(\cdot)$ in place of it and $(\cdot)$ means just a standard vector. Whereas $<\cdot>$ is often used to denote a linear span.

• Very low accepted rate in answers to your previous questions. With all due respect, have you considered accepting some answers to those questions or at least giving some feedback about what you think about them? – Jack Nov 24 '16 at 3:23

$\langle x,y,z\rangle$ means nothing but an element of $\mathbb{R}^3$ in the context of your given link.
The author of that website explains here the distinction of $(\ )$ and $\langle\ \rangle$.