Displaying similar documents to “On chirality groups and regular coverings of regular oriented hypermaps”

Lifting of homeomorphisms to branched coverings of a disk

Bronisław Wajnryb, Agnieszka Wiśniowska-Wajnryb (2012)

Fundamenta Mathematicae

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We consider a simple, possibly disconnected, d-sheeted branched covering π of a closed 2-dimensional disk D by a surface X. The isotopy classes of homeomorphisms of D which are pointwise fixed on the boundary of D and permute the branch values, form the braid group Bₙ, where n is the number of branch values. Some of these homeomorphisms can be lifted to homeomorphisms of X which fix pointwise the fiber over the base point. They form a subgroup L π of finite index in Bₙ. For each equivalence...

The genera, reflexibility and simplicity of regular maps

Marston Conder, Jozef Širáň, Thomas Tucker (2010)

Journal of the European Mathematical Society

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This paper uses combinatorial group theory to help answer some long-standing questions about the genera of orientable surfaces that carry particular kinds of regular maps. By classifying all orientably-regular maps whose automorphism group has order coprime to g - 1 , where g is the genus, all orientably-regular maps of genus p + 1 for p prime are determined. As a consequence, it is shown that orientable surfaces of infinitely many genera carry no regular map that is chiral (irreflexible), and...

Regularity of certain sets in ℂⁿ

Nguyen Quang Dieu (2003)

Annales Polonici Mathematici

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A subset K of ℂⁿ is said to be regular in the sense of pluripotential theory if the pluricomplex Green function (or Siciak extremal function) V K is continuous in ℂⁿ. We show that K is regular if the intersections of K with sufficiently many complex lines are regular (as subsets of ℂ). A complete characterization of regularity for Reinhardt sets is also given.

Involutions of 3-dimensional handlebodies

Andrea Pantaleoni, Riccardo Piergallini (2011)

Fundamenta Mathematicae

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We study the orientation preserving involutions of the orientable 3-dimensional handlebody H g , for any genus g. A complete classification of such involutions is given in terms of their fixed points.

Some topological properties of ω -covering sets

Andrzej Nowik (2000)

Czechoslovak Mathematical Journal

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We prove the following theorems: There exists an ω -covering with the property s 0 . Under c o v ( 𝒩 ) = there exists X such that B o r [ B X is not an ω -covering or X B is not an ω -covering]. Also we characterize the property of being an ω -covering.

Universal completely regular dendrites

K. Omiljanowski, S. Zafiridou (2005)

Colloquium Mathematicae

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We define a dendrite E n which is universal in the class of all completely regular dendrites with order of points not greater than n. In particular, the dendrite E ω is universal in the class of all completely regular dendrites. The construction starts with the standard universal dendrite D n of order n described by J. J. Charatonik.

Supremum properties of Galois-type connections

Árpád Száz (2006)

Commentationes Mathematicae Universitatis Carolinae

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In a former paper, motivated by a recent theory of relators (families of relations), we have investigated increasingly regular and normal functions of one preordered set into another instead of Galois connections and residuated mappings of partially ordered sets. A function f of one preordered set X into another Y has been called (1) increasingly   g -normal, for some function g of Y into X , if for any x X and y Y we have f ( x ) y if and only if x g ( y ) ; (2) increasingly ϕ -regular, for some function ϕ ...

On the density and net weight of regular spaces

Armando Romero Morales (2007)

Colloquium Mathematicae

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We use the cardinal functions ac and lc, due to Fedeli, to establish bounds on the density and net weight of regular spaces which improve some well known bounds. In particular, we use the language of elementary submodels to establish that d ( X ) π χ ( X ) a c ( X ) for every regular space X. This generalizes the following result due to Shapirovskiĭ: d ( X ) π χ ( X ) c ( X ) for every regular space X.