A Coclassifying Map for the Inclusion of the Wedge in the Product.
A cohomological index of Fuller type for parameterized set-valued maps in normed spaces
We construct a cohomological index of the Fuller type for set-valued flows in normed linear spaces satisfying the properties of existence, excision, additivity, homotopy and topological invariance. In particular, the constructed index detects periodic orbits and stationary points of set-valued dynamical systems, i.e., those generated by differential inclusions. The basic methods to calculate the index are also presented.
A Cohomological Proof of the Torus Theorem.
A cohomology for foliated manifolds.
A combinatorial characterization of planar 2-complexes
A combinatorial interpretation of homotopy groups of polyhedra
A combinatorial theorem for a symmetric triangulation of the sphere
A common fixed point theorem for commuting expanding maps on nilmanifolds.
A comparison principle and extension of equivariant maps.
A complement to the theory of equivariant finiteness obstructions
It is known ([1], [2]) that a construction of equivariant finiteness obstructions leads to a family of elements of the groups . We prove that every family of elements of the groups can be realized as the family of equivariant finiteness obstructions of an appropriate finitely dominated G-complex X. As an application of this result we show the natural equivalence of the geometric construction of equivariant finiteness obstruction ([5], [6]) and equivariant generalization of Wall’s obstruction...
A conjecture on the unstable Adams spectral sequences for SO and U
We give a systematic account of a conjecture suggested by Mark Mahowald on the unstable Adams spectral sequences for the groups SO and U. The conjecture is related to a conjecture of Bousfield on a splitting of the E₂-term and to an algebraic spectral sequence constructed by Bousfield and Davis. We construct and realize topologically a chain complex which is conjectured to contain in its differential the structure of the unstable Adams spectral sequence for SO. A filtration of this chain complex...
A construction of noncontractible simply connected cell-like two-dimensional Peano continua
Using the topologist sine curve we present a new functorial construction of cone-like spaces, starting in the category of all path-connected topological spaces with a base point and continuous maps, and ending in the subcategory of all simply connected spaces. If one starts from a noncontractible n-dimensional Peano continuum for any n > 0, then our construction yields a simply connected noncontractible (n + 1)-dimensional cell-like Peano continuum. In particular, starting from the circle 𝕊¹,...
A constructive modification of Vietoris homology
A convenient category for directed homotopy.
A Converse to the P.A. Smith Theorem for Nonunitary Homology Spheres.
A counterexample concerning products in the shape category
We exhibit a metric continuum X and a polyhedron P such that the Cartesian product X × P fails to be the product of X and P in the shape category of topological spaces.
A Counterexample to a Conjecture of Steenrod.
A counterexample to a group completion conjecture of J. C. Moore.
A counterexample to the smoothness of the solution to an equation arising in fluid mechanics
We analyze the equation coming from the Eulerian-Lagrangian description of fluids. We discuss a couple of ways to extend this notion to viscous fluids. The main focus of this paper is to discuss the first way, due to Constantin. We show that this description can only work for short times, after which the ``back to coordinates map'' may have no smooth inverse. Then we briefly discuss a second way that uses Brownian motion. We use this to provide a plausibility argument for the global regularity for...
A criterion of SNT(X) = {[X]} for hyperformal spaces
We will give a condition characterizing spaces X with SNT(X) = {[X]} which generalizes the corresponding result of McGibbon and Moller [8] for rational H-spaces.