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Combinatoire des simplexes sans singularités I. Le cas différentiable

Jean Cerf (1998)

Annales de l'institut Fourier

On définit le bicomplexe C , , extension naturelle du complexe C engendré par un ensemble simplicial Γ . Ceci permet de définir la notion de ruban de base un cycle de C . La somme directe de l’homologie des colonnes de C , contient, outre l’homologie de C , des groupes dans lesquels se trouvent les obstructions à l’existence de rubans. Si Γ est un sous-ensemble simplicial, stable par subdivision, de l’ensemble des simplexes singuliers d’un espace topologique, l’existence de rubans entraîne l’invariance...

Combinatorial mapping-torus, branched surfaces and free group automorphisms

François Gautero (2007)

Annali della Scuola Normale Superiore di Pisa - Classe di Scienze

We give a characterization of the geometric automorphisms in a certain class of (not necessarily irreducible) free group automorphisms. When the automorphism is geometric, then it is induced by a pseudo-Anosov homeomorphism without interior singularities. An outer free group automorphism is given by a 1 -cocycle of a 2 -complex (a standard dynamical branched surface, see [7] and [9]) the fundamental group of which is the mapping-torus group of the automorphism. A combinatorial construction elucidates...

Combinatorics and topology - François Jaeger's work in knot theory

Louis H. Kauffman (1999)

Annales de l'institut Fourier

François Jaeger found a number of beautiful connections between combinatorics and the topology of knots and links, culminating in an intricate relationship between link invariants and the Bose-Mesner algebra of an association scheme. This paper gives an introduction to this connection.

Currently displaying 861 – 880 of 4977