منابع مشابه
Extensions of Maps as Fibrations and Cofibrations
Suppose /: X —• Y is a map of 1-connected spaces. In the "stable" range, roughly where the connectivity of Y exceeds the homology, or homotopy, dimension of X, it is well known that / can be extended as a cofibration C — X — Y, or respectively a fibration X — Y — B. A criterion is given for the existence of such extensions in a less restrictive "metastable" range. A main result is that if / is ...
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On the category of bisimplicial sets there are different Quillen closed model structures associated to various definitions of fibrations. In one of them, which is due to Bousfield and Kan and that consists of seeing a bisimplicial set as a simplicial object in the category of simplicial sets, fibrations are those bisimplicial set maps such that each of the induced simplicial set maps is a Kan f...
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We give a bound on embedding dimensions of geometric generic fibers in terms of the dimension of the base, for fibrations in positive characteristic. This generalizes the well-known fact that for fibrations over curves, the geometric generic fiber is reduced. We illustrate our results with Fermat hypersurfaces and genus one curves.
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Dataaow networks are a paradigm for concurrent computation in which a collection of concurrently and asynchronously executing processes communicate by sending messages over FIFO message channels. In a previous paper, we showed that dataaow networks could be represented as certain spans in a category of automata, or more abstractly, in a category of domains, and we identiied some universal prope...
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Domain swapping is a term used to describe a process when two or more protein chains exchange identical structural elements. Some cases of amyloid formation can be explained through a domain swapping mechanism therefore this deserves theoretical consideration and studying. It has been demonstrated that diverse proteins in sequence and structure are able to oligomerize via domain swapping. This ...
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ژورنال
عنوان ژورنال: The Quarterly Journal of Mathematics
سال: 1979
ISSN: 0033-5606,1464-3847
DOI: 10.1093/qmath/30.4.505