The actions of Sn+1 and Sn on the cohomology ring of a Coxeter arrangement of type An-1.
The classification of space groups.
The construction of affine structures on virtually nilpotent groups.
The Dehn functions of and
For at least 3, the Dehn functions of and are exponential. Hatcher and Vogtmann proved that they are at most exponential, and the complementary lower bound in the case was established by Bridson and Vogtmann. Handel and Mosher completed the proof by reducing the lower bound for bigger than 3 to the case . In this note we give a shorter, more direct proof of this last reduction.
The diameter function on the space of space form
The Equivariant Bundle Subtraction Theorem and its applications
In the theory of transformation groups, it is important to know what kind of isotropy subgroups of G do occur at points of the space upon which the given group G acts. In this article, for a finite group G, we prove the Equivariant Bundle Subtraction Theorem (Theorem 2.2) which allows us to construct smooth G-manifolds with prescribed isotropy subgroups around the G-fixed point sets. In Theorem 0.1, we restate Oliver's result about manifolds M and G-vector bundles over M that occur, respectively,...
The fixed-point conjecture and monoids on a manifold with boundary.
The free rank of symmetry of (Sn)k.
The genus of PSl2 (q).
The graded Lie algebra of a Kähler group.
The hyperKähler geometry associated to Wolf spaces
Sia un grupo di Lie compatto e semplice. Sia la più piccola orbita nilpotente non-banale nell'algebra di Lie complessa . Si presenta una costruzione diretta di teoria di Lie delle metriche iperKahler su con potenziale Kahleriano -invariante e compatibili con la forma simplettica complessa di Kostant-Kirillov-Souriau. In particolare si ottengono le metriche iperKahler dei fibrati associati sugli spazi di Wolf (spazi simmetrici quaternionali a curvatura scalare positiva).
The Image of the Atiyah-Bott Map.
The Kahn-Priddy Theorem and Equivariant Vector Fields on Spheres.
The Lie affine foliations on 4-manifolds.
The topological spherical space form problem I
The Topological Version of Groups Generated by Reflections.
The Topological-Euclidean Space Form Problem.
Topological classification of multiaxial -actions (with an appendix by Jared Bass)
This paper begins the classification of topological actions on manifolds by compact, connected, Lie groups beyond the circle group. It treats multiaxial topological actions of unitary and symplectic groups without the dimension restrictions used in earlier works by M. Davis and W. C. Hsiang on differentiable actions. The general results are applied to give detailed calculations for topological actions homotopically modeled on standard multiaxial representation spheres. In the present topological...
Topological conjugation classes of tightly transitive subgroups of Homeo₊(ℝ)
Let ℝ be the real line and let Homeo₊(ℝ) be the orientation preserving homeomorphism group of ℝ. Then a subgroup G of Homeo₊(ℝ) is called tightly transitive if there is some point x ∈ X such that the orbit Gx is dense in X and no subgroups H of G with |G:H| = ∞ have this property. In this paper, for each integer n > 1, we determine all the topological conjugation classes of tightly transitive subgroups G of Homeo₊(ℝ) which are isomorphic to ℤⁿ and have countably many nontransitive points.
Topological transitivity of solvable group actions on the line ℝ
Let ϕ:G → Homeo₊(ℝ) be an orientation preserving action of a discrete solvable group G on ℝ. In this paper, the topological transitivity of ϕ is investigated. In particular, the relations between the dynamical complexity of G and the algebraic structure of G are considered.