# What does the notation $p/|p|$ mean in topology?

What does the notation $p/|p|$ mean in topology? I guess it's associated with boundary/restriction of a map, but don't know how it is strictly defined...

• What is $p$? In what context have you seen this notation? For me this could be a non-zero point $p$ in $\Bbb R^n$, divided by its norm $\|p\|$. – Watson Mar 25 '16 at 13:55
• Guillemin Pollack , page 81. Here is a link: math.ucr.edu/~res/math260s10/old/difftopGP.pdf – futures Mar 25 '16 at 13:56

It just refers to the function $f(x)=p(x)/\|p(x)\|$, where the $\|\cdot \|$ term is the Euclidean norm, and $p$ has codomain $\Bbb R^n$. This is well defined and smooth if $p$ is never zero, and has image on the unit sphere.