منابع مشابه
Branched Coverings Defined by Triangulations
A canonical branched covering over each sufficiently good simplicial complex is constructed. Its structure depends on the combinatorial type of the complex. In this way, each closed orientable 3-manifold arises as a branched covering over S3 from some triangulation of S3. This result is related to a theorem of Hilden [9] and Montesinos [16]. The branched coverings introduced admit a rich theory...
متن کاملAlgorithmic aspects of branched coverings
This is the announcement, and the long summary, of a series of articles on the algorithmic study of Thurston maps. We describe branched coverings of the sphere in terms of group-theoretical objects called bisets, and develop a theory of decompositions of bisets. We introduce a canonical “Levy” decomposition of an arbitrary Thurston map into homeomorphisms, metrically-expanding maps and maps dou...
متن کامل- homomorphisms , transfers and branched coverings
The main purpose is to characterise continuous maps that are n-branched coverings in terms of induced maps on the rings of functions. The special properties of Frobenius n-homomorphisms between two function spaces that correspond to n-branched coverings are determined completely. Several equivalent definitions of a Frobenius n-homomorphism are compared and some of their properties are proved. A...
متن کاملComputing pseudotriangulations via branched coverings
We describe an efficient algorithm to compute a pseudotriangulation of a finite planar family of pairwise disjoint convex bodies presented by its chirotope. The design of the algorithm relies on a deepening of the theory of visibility complexes and on the extension of that theory to the setting of branched coverings. The problem of computing a pseudotriangulation that contains a given set of bi...
متن کاملTwo Results on Branched Coverings of Grassmannians
Introduction. In this paper we present two results on branched coverings of Grassmannians.
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ژورنال
عنوان ژورنال: Michigan Mathematical Journal
سال: 1971
ISSN: 0026-2285
DOI: 10.1307/mmj/1029000633