Über Erweiterungen von Z und Z2 * Z2 durch nichteuklidische kristallographische Gruppen.
Über Gruppen von Homöomorphismen Seifertscher Faserräume und flacher Manigfaltigkeiten.
Über offene Abbildungen auf die 3-Sphäre.
Umbilical characteristic number of Lagrangian mappings of 3-dimensional pseudooptical manifolds
As shown by V. Vassilyev [V], singularities of arbitrary Lagrangian mappings of three-folds form no integral characteristic class. We show, nevertheless, that in the pseudooptical case the number of singularities counted with proper signs forms an invariant. We give a topological interpretation of this invariant, and its applications. The results of the paper may be considered as a 3-dimensional generalization of the results due to V. I. Arnold [A].
Un algorithme pour calculer l'invariant de Walker
Un contre-exemple à la conjecture de Seifert
Un nouvel invariant pour les sphères d'homologie de dimension trois
Una caracterización topológica de las involuciones en superficies de Klein.
Une obstruction pour scinder une équivalence d’homotopie en dimension
Unified quantum invariants and their refinements for homology 3-spheres with 2-torsion
For every rational homology 3-sphere with H₁(M,ℤ) = (ℤ/2ℤ)ⁿ we construct a unified invariant (which takes values in a certain cyclotomic completion of a polynomial ring) such that the evaluation of this invariant at any odd root of unity provides the SO(3) Witten-Reshetikhin-Turaev invariant at this root, and at any even root of unity the SU(2) quantum invariant. Moreover, this unified invariant splits into a sum of the refined unified invariants dominating spin and cohomological refinements of...
Uniformisation en dimension trois
Uniqueness of the embedding of a 2-complex into a 3-manifold.
Universal manifold pairings and positivity.
Unknotting number one knots are prime.
Unstable minimal surfaces and Heegaard splittings.