منابع مشابه
Pull-backs of Bundles and Homotopy Invariance
We define the pull-back of a smooth principal fibre bundle, and show that it has a natural principal fibre bundle structure. Next, we analyse the relationship between pull-backs by homotopy equivalent maps. The main result of this article is to show that for a principal fibre bundle over paracompact manifolds, there is a principal fibre bundle isomorphism between pull-backs obtained from homoto...
متن کاملReflexive Pull-backs and Base Extension
We prove that Viehweg’s moduli functor of stable surfaces is locally
متن کاملBar Complexes and Formality of Pull-backs
In this note, we show that the pull-back of a fibration by a formal map is formal. The fibration is required to be totally non-homologous to zero, and to be a formal map as well. We are here referring to the notion of formality in the setting of rational homotopy theory. This result extends a theorem of Vigué-Poirrier, [10], where it is proved that the fibre of such a fibration is a formal spac...
متن کاملPull-backs and Fibrations in Approximate Pro-categories
In this paper we introduce the category Apro-ANR called the approximate pro-category of ANR’s, whose objects are all systems of ANR’s and whose morphisms are obtained as equivalence classes of system maps for some equivalence relation. We show that any 2-sink X f −→ Z g ←− Y in Apro-ANR admits a weak pull-back and it admits a pull-back if they are systems of compact ANR’s. Moreover, it admits a...
متن کاملAn Introduction to Pull-backs of Bundles and Homotopy Invariance
We define the pull-back of a smooth principal fibre bundle, and show that it has a natural principal fibre bundle structure. Next, we analyse the relationship between pull-backs by homotopy equivalent maps. The main result of this article is to show that for a principal fibre bundle over a paracompact manifold, there is a principal fibre bundle isomorphism between pull-backs obtained from homot...
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ژورنال
عنوان ژورنال: Proceedings of the American Mathematical Society
سال: 1985
ISSN: 0002-9939
DOI: 10.1090/s0002-9939-1985-0781047-4