p-Elementary subgroups of the Cremona group

Finite abelian subgroups of the Cremona group of the plane

Nonlinearity of Some Subgroups of the Planar Cremona Group

We give some examples of nonlinear subgroups of the planar Cremona group.

Maximal Algebraic Subgroups of the Cremona Group of Three Variables Imprimitive Algebraic Subgroups of Exceptional Type

Enriques and Fano [4], [5] classified all the maximal connected algebraic subgroups of Cr3. Our aim is to give modern and rigorous proofs to their results. In [10], we studied the primitive subgroups. In this paper, we deal with exceptional imprimitive groups. The imprimitivity is an analytic notion. The natural translation of the imprimitivity in algebraic geometry is the de Jonquieres type op...

Some Subgroups of the Cremona Groups

We explore algebraic subgroups of the Cremona group Cn over an algebraically closed field of characteristic zero. First, we consider some class of algebraic subgroups of Cn that we call flattenable. It contains all tori. Linearizability of the natural rational actions of flattenable subgroups on An is intimately related to rationality of the invariant fields and, for tori, is equivalent to it. ...

THE NUMBER OF CHAINS OF SUBGROUPS OF A FINITE ELEMENTARY ABELIAN p-GROUP

The starting point for our discussion is given by the paper [5], where a formula for the number of rooted chains of subgroups of a finite cyclic group is obtained. This leads in [3] to precise expression of the well-known central Delannoy numbers in an arbitrary dimension and has been simplified in [2]. Some steps in order to determine the number of rooted chains of subgroups of a finite elemen...