Read the following German text and its official translation:
Die Gauss-Krümmung K eines Flächenstücks f:U --> R3 der Klasse C3 hängt nur von der ersten Fundamentalform ab (ist also eine Größe der inneren Geometrie). (Read in Google book)
The Gaussian curvature K of a two-dimensional surface element f : U --> R3 of class C3 depends only on the first fundamental form ("and" is consequently an intrinsic quantity of the surface). (Read in Google book)
Q1: What is the meaning and role of "ab" here? As I checked by Google translate, the translation of the sentence without "ab" is same as with "ab".
Q2: I know that it is better to add "and" in the beginning of parenthesis, but why there is no "und" in German text? Is the German sentence a complete and meaningful sentence? (without "und")
I know that the translation of "ist also" is "is thus, is consequently, ..".