On the subgroups of the Picard group.
On the Top Betti Number of Subgroups of SL(n,Z).
On three-dimensional space groups.
Operator k-theory for the group SU(n, 1).
Orders of some modular linear groups.
Outer automorphism groups of Bieberbach groups.
p-adic deformations of cohomology classes of subgroups of GL (N,Z).
Painlevé equations and complex reflections
We will explain how some new algebraic solutions of the sixth Painlevé equation arise from complex reflection groups, thereby extending some results of Hitchin and Dubrovin-- Mazzocco for real reflection groups. The problem of finding explicit formulae for these solutions will be addressed elsewhere.
Pairs of symmetries of Riemann surfaces.
Parabolic bundles, elliptic surfaces and SU (2)-representation spaces of genus zero Fuchsian groups.
Periodic linear groups factorized by mutually permutable subgroups
The aim is to investigate the behaviour of (homomorphic images of) periodic linear groups which are factorized by mutually permutable subgroups. Mutually permutable subgroups have been extensively investigated in the finite case by several authors, among which, for our purposes, we only cite J. C. Beidleman and H. Heineken (2005). In a previous paper of ours (see M. Ferrara, M. Trombetti (2022)) we have been able to generalize the first main result of J. C. Beidleman, H. Heineken (2005) to periodic...
Periodic subgroups of projective linear groups in positive characteristic
We classify the maximal irreducible periodic subgroups of PGL(q, ), where is a field of positive characteristic p transcendental over its prime subfield, q = p is prime, and × has an element of order q. That is, we construct a list of irreducible subgroups G of GL(q, ) containing the centre ×1q of GL(q, ), such that G/ ×1q is a maximal periodic subgroup of PGL(q, ), and if H is another group of this kind then H is GL(q, )-conjugate to a group in the list. We give criteria for determining...
Periodic-by-nilpotent linear groups
Periods of p-adic Schottky groups.
Plane and layer symmetry groups
Plane and layer symmetry groups
Plane Motion Groups and Virtual Poincaré Duality of Dimension Two.
Poincaré duality groups of dimension two.
Poincaré polynomials for unitary reflection groups.
Power subgroups of Hecke groups .