#### dg

I have found some interesting material at mathworld.wolfram.com but as usual there is a quantity of little incorrect details.

Is anybody willing to study a little bit of this stuff together? I am sure this stuff can give a lot of insight in the interepretation of physical problems and equations as well.

In particular now I am trying to see better the connections between surfaces described implicitly (F(

**r**)=0) or parametrically (

**r**=

**σ**(u,v)): how and when is it possible to pass from one to the other description?

Everybody willing to contribute/learn is more than welcome! :)

Dario