A note on strong Jordan separation.
A note on the height of the third Stiefel--Whitney class of the canonical vector bundles over some Grassmann manifolds
We compute the height of the third Stiefel--Whitney characteristic class of the canonical bundles over some infinite classes of Grassmann manifolds of five dimensional vector subspaces of real vector spaces.
A note on the homotopical characterization of Rn.
A note on the wick of the Casson handles
A note on topological properties of non-Hausdorff manifolds.
A Polish AR-Space with no Nontrivial Isotopy
The Polish space Y constructed in [vM1] admits no nontrivial isotopy. Yet, there exists a Polish group that acts transitively on Y.
A polyhedral 2-sphere which fails to be locally flat at just one point
A polynomial invariant of rational homology 3-spheres.
A positional characterization of the (n-1)-dimensional Sierpiński curve in (η ≠ 4)
A proof of Reidemeister-Singer’s theorem by Cerf’s methods
Heegaard splittings and Heegaard diagrams of a closed 3-manifold are translated into the language of Morse functions with Morse-Smale pseudo-gradients defined on . We make use in a very simple setting of techniques which Jean Cerf developed for solving a famous pseudo-isotopy problem. In passing, we show how to cancel the supernumerary local extrema in a generic path of functions when . The main tool that we introduce is an elementary swallow tail lemma which could be useful elsewhere.
A quick proof of the 4-dimensional stable surgery theorem.
A rational noncommutative invariant of boundary links.
A remark on the action of the mapping class group on the unit tangent bundle
We prove that the standard action of the mapping class group of a surface of sufficiently large genus on the unit tangent bundle is not homotopic to any smooth action.
A set of moves for Johansson representation of 3-manifolds
A Dehn sphere Σ in a closed 3-manifold M is a 2-sphere immersed in M with only double curve and triple point singularities. The Dehn sphere Σ fills M if it defines a cell decomposition of M. The inverse image in S² of the double curves of Σ is the Johansson diagram of Σ and if Σ fills M it is possible to reconstruct M from the diagram. A Johansson representation of M is the Johansson diagram of a filling Dehn sphere of M. Montesinos proved that every closed 3-manifold has a Johansson representation...
A short introduction to shadows of 4-manifolds
We give a self-contained introduction to the theory of shadows as a tool to study smooth 3-manifolds and 4-manifolds. The goal of the present paper is twofold: on the one hand, it is intended to be a shortcut to a basic use of the theory of shadows, on the other hand it gives a sketchy overview of some of the most recent results on shadows. No original result is proved here and most of the details of the proofs are left out.
A spectral sequence for orbifold cobordism
The aim of this paper is to introduce a spectral sequence that converges to the cobordism groups of orbifolds with given isotropy representations. In good cases the E¹-term of this spectral sequence is given by a certain cobordism group of orbibundles over purely ineffective orbifolds which can be identified with the bordism group of the classifying space of the Weyl group of a finite subgroup of O(n). We use this spectral sequence to calculate some cobordism groups of orbifolds for low dimensions,...
A Splicing formula for Casson-Walker's invariant.
A stable classification of Lefschetz fibrations.
A sufficient condition for a group of homeomorphisms to be affine.
A Surgery Sequence in Dimension Four; The Relations with Knot Concordance.