15 citations · 22 across the 12 of their papers we have counts for
4 papers · 1 filter
Characterization of affine surfaces with a torus action by their automorphism groups
Alvaro Liendo, Andriy Regeta, Christian Urech
In this paper we prove that if two normal affine surfaces and have isomorphic automorphism groups, then every connected algebraic group acting regularly and faithfully on…
Simple groups of birational transformations in dimension two
Christian Urech
We classify simple groups that act by birational transformations on compact complex Kähler surfaces. Moreover, we show that every finitely generated simple group that acts non-triv…
Subgroups of elliptic elements of the Cremona group
Christian Urech
The Cremona group is the group of birational transformations of the complex projective plane. In this paper we classify its subgroups that consist only of elliptic elements using e…
A new presentation of the plane Cremona group
Christian Urech, Susanna Zimmermann
We give a presentation of the plane Cremona group over an algebraically closed field with respect to the generators given by the Theorem of Noether and Castelnuovo. This presentati…