A survey to determine the role of local Glossina species on the transmission of human sleeping sickness has been carried out in the Ikoma/Seronera/Kilimafedha triangle. Three different tsetse species were encountered; they were G. swyn¬ nertoni, G. pallidipes and G. brevipalpis. Out of 6,348 G. swynnertoni and 623 G. pallidipes examined not a single carried salivary gland infection. G. swynnert...

The largest Fischer 3-transposition group M(24) acts ag-transitively on a 3-local incidence geometry G(M(24)) which is a c-extension of the dual polar space associated with the group O 7 (3). The action of the simple commutator subgroup M(24) 0 is still ag-transitive. We show that G(M(24)) is characterized by its diagram under the ag-transitivity assumption. The result implies in particular tha...

We localize and strengthen Katona’s idea of an edge-toughness to a local topological toughness. We disprove a conjecture of Katona concerning the conection between edge-toughness and factors. For the topological toughness we prove a theorem similar to Katona’s 2k-factorconjecture, which turned out to be false for his edge-toughness. We prove, that besides this the topological toughness has near...

Let G be a directed graph embedded in a surface. A map φ : E(G) → R is a tension if for every circuit C ⊆ G, the sum of φ on the forward edges of C is equal to the sum of φ on the backward edges of C. If this condition is satisfied for every circuit of G which is a contractible curve in the surface, then φ is a local tension. If 1 ≤ |φ(e)| ≤ α − 1 holds for every e ∈ E(G), we say that φ is a (l...

For a vertex v of a graph G, we denote by d(v) the degree of v. The local connectivity κ(u, v) of two vertices u and v in a graph G is the maximum number of internally disjoint u–v paths in G. Clearly, κ(u, v) ≤ min{d(u), d(v)} for all pairs u and v of vertices in G. We call a graph G maximally local connected when κ(u, v) = min{d(u), d(v)} for all pairs u and v of distinct vertices in G. Let p...