#### G. Berhuy, Z. Reichstein, *
On the notion of canonical dimension for algebraic groups,
* Advances in Mathematics, 198 (2005), 128--171.

** Abstract: **
We define and study a new numerical invariant of
an algebraic group action; we call it the canonical dimension.
We then apply the resulting theory to the problem of
computing the minimal number of parameters required
to define a generic hypersurface of degree d in P^{n-1}.

PDF file

DVI file