activity
19992005
most citedLocally nilpotent derivations on affine surfaces with a $\C^*$-action

44 citations · 52 across the 7 of their papers we have counts for

collaborators

12 papers

math.AC2005

Power series rings and projectivity

R. -O. Buchweitz, H. Flenner

We show that a formal power series ring over a noetherian ring is not a projective module unless is artinian. However, if is local, then $A[[X]…

math.AG2005

On a result of Miyanishi-Masuda

Hubert Flenner, Mikhail Zaidenberg

Let be an affine surface admitting a unique affine ruling and a -action. Assume that the ruling has a unique degenerate fibre and that this fibre is irreducible. I…

math.AC2005

Codimension and connectedness of degeneracy loci over local rings

Hubert Flenner, Bernd Ulrich

We deduce results on the dimension and connectedness of degeneracy loci of maps of finite modules over a local noetherian ring . We show for instance…

math.AG20048 cited

On the uniqueness of -actions on affine surfaces

Hubert Flenner, Mikhail Zaidenberg

We prove that a normal affine surface over admits an effective action of a maximal torus () such that any other effective -act…

math.AG200444 cited

Locally nilpotent derivations on affine surfaces with a $\C^*$-action

Hubert Flenner, Mikhail Zaidenberg

We give a classification of normal affine surfaces admitting an algebraic group action with an open orbit. In particular an explicit algebraic description of the affine coordinate…

math.AG2002

A Note on Generic Projections

Hubert Flenner, Mirella Manaresi

Let be a subvariety of dimension and a generic point. If the tangent variety Tan is equal to then for…