12 citations · 16 across the 5 of their papers we have counts for
8 papers
The derived length of subgroups of the Cremona group
Jean-Philippe Furter, Isac Hedén
We prove that the maximal derived length of a solvable subgroup of the plane Cremona group over is equal to . The main difficulty is the case of subgroups containing…
Borel subgroups of the plane Cremona group
Jean-Philippe Furter, Isac Hedén
It is well known that all Borel subgroups of a linear algebraic group are conjugate. This result also holds for the automorphism group of the affine…
Rees algebras of additive group actions
Adrien Dubouloz, Isac Hedén, Takashi Kishimoto
We establish basic properties of a sheaf of graded algebras canonically associated to every relative affine scheme endowed with an action of the additive grou…
Equivariant extensions of Ga-torsors over punctured surfaces
Adrien Dubouloz, Isac Hedén, Takashi Kishimoto
Motivated by the study of the structure of algebraic actions the additive group on affine threefolds X, we consider a special class of such varieties whose algebraic quotient morph…
The decomposition groups of plane conics and plane rational cubics
Tom Ducat, Isac Hedén, Susanna Zimmermann
The decomposition group of an irreducible plane curve is the subgroup of birational maps which restrict to a…
The decomposition group of a line in the plane
Isac Hedén, Susanna Zimmermann
We show that the decomposition group of a line in the plane, i.e. the subgroup of plane birational transformations that send to itself birationally, is generated by its ele…
Russell's hypersurface from a geometric point of view
Isac Hedén
We give a new proof of Makar-Limanov's theorem, which states that Russell's hypersurface is not isomorphic to affine three space.
The group of Cremona transformations generated by linear maps and the standard involution
Jérémy Blanc, Isac Hedén
This article studies the group generated by automorphisms of the projective space of dimension and by the standard birational involution of degree . Every element of this gr…