Isomorphisms of some graph coverings
نویسنده
چکیده
Let G be a connected graph and r a group of automorphisms of G. We enumerate the number of r-isomorphism classes of derived graph coverings of G with voltages in a finite field of prime order P (>2).
منابع مشابه
Quandle Coverings and Their Galois Correspondence
This article establishes the algebraic covering theory of quandles. For every connected quandle Q with base point q ∈ Q, we explicitly construct a universal covering p : (Q̃, q̃) → (Q,q). This in turn leads us to define the algebraic fundamental group π1(Q,q) := Aut(p) = {g ∈ Adj(Q)′ | qg = q}, where Adj(Q) is the adjoint group of Q. We then establish the Galois correspondence between connected c...
متن کاملDISCRETE MATHEMATICS Line hypergraphs
In this paper, we introduce a new multivalued function ~ called the line hypergraph. The function ~ generalizes two classical concepts at once, namely, of the line graph and the dual hypergraph. In terms of this function, proofs of some known theorems on line graphs can be unified and their more general versions can be obtained. Three such theorems are considered here, namely, the Berge theorem...
متن کاملCoverings, matchings and paired domination in fuzzy graphs using strong arcs
The concepts of covering and matching in fuzzy graphs using strong arcs are introduced and obtained the relationship between them analogous to Gallai’s results in graphs. The notion of paired domination in fuzzy graphs using strong arcs is also studied. The strong paired domination number γspr of complete fuzzy graph and complete bipartite fuzzy graph is determined and obtained bounds for the s...
متن کاملTypical circulant double coverings of a circulant graph
Several isomorphism classes of graph coverings of a graph G have been enumerated by many authors. Kwak and Lee (Canad. J. Math. XLII (1990) 747) enumerated the isomorphism classes of graph bundles and those of n-fold coverings with respect to a group of automorphisms of the base graph G which 9x a spanning tree. Hofmeister (Discrete Math. 98 (1991) 175) independently enumerated the isomorphism ...
متن کاملClassifications of special double-coverings associated to a non-orientable surface
This paper investigates some possible actions ”à la Johnson” on the set with 2 elements, denoted by E , of Spinstructures which are interpreted as special Z2-coverings of a trivial S−fibration over a non-orientable surface Ng+1. The group acting is first a group of orthogonal isomorphisms of (H1(Ng+1;Z2), ·). A second approach is to consider the subspace of E (with 2 elements) coming from speci...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Discrete Mathematics
دوره 128 شماره
صفحات -
تاریخ انتشار 1994