Ueber die Eigenschaften des reinen Chloraethyls

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Total Domination in Graphs with Given Girth

A set S of vertices in a graph G without isolated vertices is a total dominating set of G if every vertex of G is adjacent to some vertex in S. The minimum cardinality of a total dominating set of G is the total domination number γ _t (G) of G. In this paper, we establish an upper bound on the total domination number of a graph with minimum degree at least two in terms of its order and girth. We prove that if G is a graph of order n with minimum degree at least two and girth g, then γ _t (G) ≤ n/2 + n/g, and this bound is sharp. Our proof is an interplay between graph theory and transversals in hypergraphs. Michael A. Henning: Research supported in part by the South African National Research Foundation and the University of KwaZulu-Natal.     

Neutral pion production at 350 MeV/u in the system20Ne +27Al

π⁰ -production probability of (9± 2)· 10^{? 3} per²⁰Ne+Al reaction has been measured at 350 MeV/u using the Two Arm Photon Spectrometer TAPS. This yield is consistent with an interpolation of published π-production rates in heavy ion collisions.