منابع مشابه
Non-Abelian Sequenceable Groups Involving ?-Covers
A non-abelian finite group is called sequenceable if for some positive integer , is -generated ( ) and there exist integers such that every element of is a term of the -step generalized Fibonacci sequence , , , . A remarkable application of this definition may be find on the study of random covers in the cryptography. The 2-step generalized sequences for the dihedral groups studi...
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Two strings u and v are said to be Abelian equivalent if u is a permutation of the characters of v. We introduce two new regularities on strings w.r.t. Abelian equivalence, called Abelian covers and Abelian runs, which are generalizations of covers and runs of strings, respectively. We show how to determine in O(n) time whether or not a given string w of length n has an Abelian cover. Also, we ...
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Let G be any abelian group and {asGs}ks=1 be a finite system of cosets of subgroups G1, . . . , Gk. We show that if {asGs} k s=1 covers all the elements of G at least m times with the coset atGt irredundant then [G : Gt] 6 2 and furthermore k > m + f([G : Gt]), where f( ∏ r i=1 p αi i ) = ∑ r i=1 αi(pi − 1) if p1, . . . , pr are distinct primes and α1, . . . , αr are nonnegative integers. This ...
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We study normal finite abelian covers of smooth varieties. In particular we establish combinatorial conditions so that a normal finite abelian cover of a smooth variety is Gorenstein or locally complete intersection.
متن کاملElementary Abelian Covers of Graphs
Let CG (X ) be the set of all (equivalence classes of) regular covering projections of a given connected graph X along which a given group G ≤ Aut X of automorphisms lifts. There is a natural lattice structure on CG (X ), where ℘1 ≤ ℘2 whenever ℘2 factors through ℘1. The sublattice CG (℘) of coverings which are below a given covering ℘ : X̃ → X naturally corresponds to a lattice NG (℘) of certai...
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ژورنال
عنوان ژورنال: Boletim da Sociedade Brasileira de Matem�tica
سال: 1998
ISSN: 0100-3569,1678-7714
DOI: 10.1007/bf01245874