A note on minimal Galois embeddings of abelian surfaces
AK-invariant, some conjectures, examples and counterexamples
In my talk I am going to remind you what is the AK-invariant and give examples of its usefulness. I shall also discuss basic conjectures about this invariant and some positive and negative results related to these conjectures.
Algebraic automorphisms of smooth affine surfaces.
Automorphism groups of orientable elliptic-hyperelliptic Klein surfaces.
Automorphism groups of rational elliptic surfaces with section and constant J-map
In this paper, the automorphism groups of relatively minimal rational elliptic surfaces with section which have constant J-maps are classified. The ground field is ℂ. The automorphism group of such a surface β: B → ℙ1, denoted by Au t(B), consists of all biholomorphic maps on the complex manifold B. The group Au t(B) is isomorphic to the semi-direct product MW(B) ⋊ Aut σ (B) of the Mordell-Weil groupMW(B) (the group of sections of B), and the subgroup Aut σ (B) of the automorphisms preserving a...
Automorphisms of order three on numerical Godeaux surfaces
We prove that a numerical Godeaux surface cannot have an automorphism of order three.
Big groups of automorphisms of some Klein surfaces.
Sea Xp una superficie de Klein compacta con borde de gen algebraico p ≥ 2. Se sabe que si G es un grupo de automorfismos de Xp entonces |G| ≤ 12(p- 1). Se dice que G es un grupo grande de gen p si |G| > 4(p -1). En el presente artículo se halla una familia de enteros p para los que el único grupo grande de gen p son los grupos diédricos. Esto significa que, en términos del gen real introducido por C. L. May, para tales valores de p no existen grupos grandes de gen real p.
Families of supersingular abelian surfaces
Finite groups of automorphisms of K3 surfaces and the Mathieu group.
Global minimal models for endomorphisms of projective space
We prove the existence of global minimal models for endomorphisms of projective space defined over the field of fractions of a principal ideal domain.
Holomorphic automorphisms of quadrics.
Introduction to actions of algebraic groups
These notes present some fundamental results and examples in the theory of algebraic group actions, with special attention to the topics of geometric invariant theory and of spherical varieties. Their goal is to provide a self-contained introduction to more advanced lectures.
Involutions on surfaces with p_g = q = 1.
Irreducible identity sets for polynomial autormorphisms.
K3 surfaces with a symplectic automorphism of order 11
Lectures on spherical and wonderful varieties
These notes contain an introduction to the theory of spherical and wonderful varieties. We describe the Luna-Vust theory of embeddings of spherical homogeneous spaces, and explain how wonderful varieties fit in the theory.
On abelian automorphism group of a surface of general type.
On orbits of the automorphism group on an affine toric variety
Let X be an affine toric variety. The total coordinates on X provide a canonical presentation of X as a quotient of a vector space by a linear action of a quasitorus. We prove that the orbits of the connected component of the automorphism group Aut(X) on X coincide with the Luna strata defined by the canonical quotient presentation.
On stable conjugacy of finite subgroups of the plane Cremona group, I
We discuss the problem of stable conjugacy of finite subgroups of Cremona groups. We compute the stable birational invariant H 1(G, Pic(X)) for cyclic groups of prime order.
On the automorphisms of surfaces of general type in positive characteristic
Here we give an explicit polynomial bound (in term of and not depending on the prime ) for the order of the automorphism group of a minimal surface of general type defined over a field of characteristic .