Cosymplectic and α-cosymplectic Lie algebras
Countable dense homogeneous filters and the Menger covering property
We present a ZFC construction of a non-meager filter which fails to be countable dense homogeneous. This answers a question of Hernández-Gutiérrez and Hrušák. The method of the proof also allows us to obtain for any n ∈ ω ∪ {∞} an n-dimensional metrizable Baire topological group which is strongly locally homogeneous but not countable dense homogeneous.
Countable products of LCA groups: their closed subgroups, quotients and duality properties
Counting arithmetic subgroups and subgroup growth of virtually free groups
Let be a -adic field, and let endowed with the Haar measure determined by giving a maximal compact subgroup measure . Let denote the number of conjugacy classes of arithmetic lattices in with co-volume bounded by . We show that under the assumption that does not contain the element , where denotes the -th root of unity over , we have where denotes the order of the residue field of .
Counting problems and semisimple groups.
Covariant approach of the dynamics of particles in external gauge fields, Killing tensors and quantum gravitational anomalies.
Covariant differential operators.
Covariant wave-equations, the Galilei group, and the magnetic moment of the electron
Covering locally compact groups by less than many translates of a compact nullset
Gruenhage asked if it was possible to cover the real line by less than continuum many translates of a compact nullset. Under the Continuum Hypothesis the answer is obviously negative. Elekes and Stepr mans gave an affirmative answer by showing that if is the well known compact nullset considered first by Erdős and Kakutani then ℝ can be covered by cof() many translates of . As this set has no analogue in more general groups, it was asked by Elekes and Stepr mans whether such a result holds for...
Covering maps over solenoids which are not covering homomorphisms
Let Y be a connected group and let f: X → Y be a covering map with the total space X being connected. We consider the following question: Is it possible to define a topological group structure on X in such a way that f becomes a homomorphism of topological groups. This holds in some particular cases: if Y is a pathwise connected and locally pathwise connected group or if f is a finite-sheeted covering map over a compact connected group Y. However, using shape-theoretic techniques and Fox's notion...
Coverings and dimensions in infinite profinite groups
Answering a question of Miklós Abért, we prove that an infinite profinite group cannot be the union of less than continuum many translates of a compact subset of box dimension less than 1. Furthermore, we show that it is consistent with the axioms of set theory that in any infinite profinite group there exists a compact subset of Hausdorff dimension 0 such that one can cover the group by less than continuum many translates of it.
Coverings and ring-groupoids.
Criterion for proper actions on homogeneous spaces of reductive groups.
Croissance polynomiale et périodes des fonctions harmoniques
Cross Sections and an Explicit Formula for the Plancherel Measure on a Nilpotent Lie Group.
Cross sections for quotient maps of locally compact groups.
Crossed Products of Communtation Systems.
Crystallographic actions on Lie groups and post-Lie algebra structures
This survey on crystallographic groups, geometric structures on Lie groups and associated algebraic structures is based on a lecture given in the Ostrava research seminar in .
Currents on Lie groups.
Curvature of a semi-direct extension of a Heisenberg type nilpotent group