Can't understand the meaning of some symbols

shakgoku

1. The problem statement, all variables and given/known data
This is an extract from elements of mechanics by giovanni.
I'[m unable to understand the meaning of [tex]R^d[/tex] and [tex]C^\infty[/tex]

http://flic.kr/p/9K8P7p


2. Relevant equations



3. The attempt at a solution

tiny-tim

hi shakgoku!

R^d is the same as Rⁿ …

i assume "d" stands for "dimension"

and C^∞ is the space of functions which are differentiable "infinitely many" times

shakgoku

Hey tiny-tim!

Thank you , now everything in the page makes sense to me! :)