In 3-dimensional Euclidean space there exist two exceptional polyhedra, the rhombic dodecahedron and triacontahedron, only known polytopes (besides polygons) that are edge-transitive without being vertex-transitive. We show these polyhedra do not have higher-dimensional analogues, is, in dimension d ? 4, edge-transitivity of convex implies vertex-transitivity.More generally, we give a classific...

A graph G admits an H-covering if every edge of belongs to a subgraph isomorphic given H. is said be H-magic there exists bijection f:V(G)∪E(G)→{1,2,…,|V(G)|+|E(G)|} such that wf(H′)=∑v∈V(H′)f(v)+∑e∈E(H′)f(e) constant, for H′ In particular, H-supermagic f(V(G))={1,2,…,|V(G)|}. When H complete K2, H-(super)magic labeling edge-(super)magic labeling. Suppose F-covering and two graphs F We define (...

Extending relational algebra and rela-tional calculus with set-valued attributes and aggregate functions, ACM Transac-a tuple t in I, produces the output of the query on I ? ftg. Then both proofs in 9] show how to use this assumption to produce an expression in rst-order logic plus g that computes the transitive closure of a chain. Since the construction of 9] does not assume any auxiliary data...

A digraph D is k-transitive if the existence of a directed path (v0, v1, . . . , vk), of length k implies that (v0, vk) ∈ A(D). Clearly, a 2-transitive digraph is a transitive digraph in the usual sense. Transitive digraphs have been characterized as compositions of complete digraphs on an acyclic transitive digraph. Also, strong 3 and 4-transitive digraphs have been characterized. In this work...

In [5] we showed, that a doubly transitive, non-solvable dimensional dual hyperoval D is either isomorphic to the Mathieu dual hyperoval or to a quotient of a Huybrechts dual hyperoval. In order to determine the doubly transitive dimensional dual hyperovals, it remains to classify the doubly transitive, solvable dimensional dual hyperovals and this paper is a contribution to this problem. A dou...

it is well known fact that binary relations are generalized mathematical functions. contrary to functions from domain to range, binary relations may assign to each element of domain two or more elements of range. some basic operations on functions such as the inverse and composition are applicable to binary relations as well. depending on the domain or range or both are fuzzy value fuzzy set, i...

This paper examines the complexity of hybrid logics over transitive frames and transitive trees. We show that satisfiability over transitive frames for the hybrid language extended with ↓ is NEXPcomplete. This is in contrast to undecidability of satisfiability over arbitrary frames for this language [2]. We also show that adding @ or the past modality leads to undecidability over transitive fra...

IS rel)re:se!otlng vertex-transitive as coset to allow us to obtain new results eral older results concerning the numbers transitive that are not 1 studied for more than a now, vertex-transitive graphs have quite great deal of activity. Their rich groups of automorphisms make from both the point of view of groups as well as of combinatorics. Among the most recent achievements, we can mention th...

We discuss the relation between (topological) transitivity and strong transitivity of dynamical systems. We show that a transitive and open self-map of a compact metric space satisfying a certain expanding condition is strongly transitive. We also prove a couple of results for interval maps; for example it is shown that a transitive piecewise monotone interval map is strongly transitive.

A graph Γ is said to be locally (G, 2)-arc transitive for G a subgroup of Aut(Γ) if, for any vertex α of Γ, G is transitive on the 2-arcs of Γ starting at α. In this talk, we will discuss general results involving locally (G, 2)-arc transitive graphs and recent progress toward the classification of the locally (G, 2)-arc transitive graphs, where Sz(q) ≤ G ≤ Aut(Sz(q)), q = 2 for some k ∈ N. In ...