Rational category of the space of sections of a nilpotent bundle.
Rational Co-H-Spaces.
Rational evalutation subgroups.
Rational fibrations homogeneous spaces with positive Euler characteristics and Jacobians
We show that an orientable fibration whose fiber has a homotopy type of homogeneous space with rank is totally non homologous to zero for rational coefficients. The Jacobian formed by invariant polynomial under the Weyl group of plays a key role in the proof. We also show that it is valid for mod. coefficients if does not divide the order of the Weyl group of .
Rational fibrations in differential homological algebra.
Rational formality of function spaces.
Rational homotopy of Serre fibrations
In rational homotopy theory, we show how the homotopy notion of pure fibration arises in a natural way. It can be proved that some fibrations, with homogeneous spaces as fibre are pure fibrations. Consequences of these results on the operation of a Lie group and the existence of Serre fibrations are given. We also examine various measures of rational triviality for a fibration and compare them with and whithout the hypothesis of pure fibration.
Rational Hopf G-spaces with two nontrivial homotopy group systems
Let G be a finite group. We prove that every rational G-connected Hopf G-space with two nontrivial homotopy group systems is G-homotopy equivalent to an infinite loop G-space.
Rational models of solvmanifolds with Kählerian structures.
We investigate the existence of symplectic non-Kählerian structures on compact solvmanifolds and prove some results which give strong necessary conditions for the existence of Kählerian structures in terms of rational homotopy theory. Our results explain known examples and generalize the Benson-Gordon theorem (Benson and Gordon (1990); our method allows us to drop the assumption of the complete solvability of G).
Rational toral ranks in certain algebras.
Rationalization of Hopf G-Spaces..
Rétractes d'un espace
Notre but dans ce texte est de montrer le résultat suivant : Si est un C.W. complexe, simplement connexe, de type fini, avec finiment engendré comme algèbre de Lie, alors, à équivalence d’homotopie rationnelle près, il n’existe qu’un nombre fini de rétractes de . L’existence d’un nombre fini de rétractes a été obtenue par L. Renner en 1990 dans le cas où est finiment engendré en tant que -algèbre. Notre résultat élargit ainsi le cadre des espaces n’ayant, à équivalence d’homotopie rationnelle...
Rigidity Properties of Compact Lie Groups Modulo Maximal Tori.