We present the results of a set of numerical simulations aiming at evaluating the effects of cluster galaxies on the arc statistics. At this goal we use nine different galaxy clusters obtained from N-body simulations. We mimic the presence of a population of galaxies inside each cluster, trying to reproduce the observed luminosity function and the spatial distribution. We compare the statistica...

It belongs to the folklore that graph grammars can be seen as a proper generalisation of Petri nets. In this paper we show how this intuitive relationship can be made formal. The double-pushout approach to graph rewriting turns out to be strictly related to Petri nets with read and inhibitor arcs, while the single-pushout approach has strong connections to Petri nets with read and reset arcs.

Two models of a random digraph on n vertices, D(n, number of arcs = m) and D(n,Prob(arc) = p) are studied. In 1990 R. Karp for D(n, p = c/n) and independently T. Luczak for D(n,m = cn) proved that for c > 1, with probability tending to 1, there is an unique strong component of size of order n. Karp showed, in fact, that the giant component has likely size asymptotic to nθ, where θ = θ(c) is the...

Context. The Cluster Lensing And Supernovae survey with Hubble (CLASH) is Hubble Space Telescope (HST) MultiCycle Treasury programme that observes 25 massive galaxy clusters, 20 of which were X-ray-selected to preferably choose dynamically relaxed clusters and 5 additional “high magnification” clusters which were selected based on their optical lensing properties. CLASH aims to study the dark m...

One of the most important issues for Muslim philosophers is the continuous imaginal world and its relationship with the discontinuous imaginative faculty. The continuous imaginal world is a perceptive faculty of the soul known as the faculty of imagination. The discontinuous imaginative faculty is the order of the universe called the imaginal world, which Muslim philosophers have portrayed in a...

Let $T$ be a non-trivial tournament. An arc is emph{$t$-pancyclic} in $T$, if it is contained in a cycle of length $ell$ for every $tleq ell leq |V(T)|$. Let $p^t(T)$ denote the number of $t$-pancyclic arcs in $T$ and $h^t(T)$ the maximum number of $t$-pancyclic arcs contained in the same Hamiltonian cycle of $T$. Moon ({em J. Combin. Inform. System Sci.}, {bf 19} (1994), 207-214) showed that $...