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
Curved Casimir operators and the BGG machinery.
Curves and Formal (Co) Groups.
Cuspidal functions and Diophantine approximation.
Cuspidal local systems and graded Hecke algebras, I
Cut locus and optimal synthesis in the sub-Riemannian problem on the group of motions of a plane*
The left-invariant sub-Riemannian problem on the group of motions (rototranslations) of a plane SE(2) is considered. In the previous works [Moiseev and Sachkov, ESAIM: COCV, DOI: 10.1051/cocv/2009004; Sachkov, ESAIM: COCV, DOI: 10.1051/cocv/2009031], extremal trajectories were defined, their local and global optimality were studied. In this paper the global structure of the exponential mapping is described. On this basis an explicit characterization of the cut locus and Maxwell set is obtained....