The magic sets rewriting technique (cf. [Ull89]) seems to be the most promising approach to evaluating queries bottom-up for database systems with a powerful view concept. This is in particular the case for systems which will implement the new SQL3 standard and hence will allow the de nition of recursive views. It has been shown that bottom-up query evaluation via magic sets is basically equiva...

A (p; q)-graph G is edge-magic if there exists a bijective function f :V (G)∪E(G)→{1; 2; : : : ; p + q} such that f(u) + f(v) + f(uv)= k is a constant, called the valence of f, for any edge uv of G. Moreover, G is said to be super edge-magic if f(V (G))= {1; 2; : : : ; p}. In this paper, we present some necessary conditions for a graph to be super edge-magic. By means of these, we study the sup...

An anti-magic labeling of a finite simple undirected graph with p vertices and q edges is a bijection from the set of edges to the set of integers {1, 2, ..., q} such that the vertex sums are pairwise distinct, where the vertex sum at vertex u is the sum of labels of all edges incident to such vertex. A graph is called anti-magic if it admits an antimagic labeling. Hartsfield and Ringel conject...

Unlike wired networks, wireless networks do not come with links. Rather, links have to be fashioned out of the ether by nodes choosing neighbors to connect to. Moreover the location of the nodes may be random. The question that we resolve is: How many neighbors should each node be connected to in order that the overall network is connected in a multi-hop fashion? We show that in a network with ...

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Huizinga [Hui71] identifies several formal characteristics which games share with magic rituals that are bound to a ”magic circle”. He states that games are explicitly defined by the space within which they take place, the time a game or play lasts, and the rules that are active during the game/play. Participants of a game must freely agree to these changes in their ordinary life to be part of ...

tion " of poverty. It is impossible, by waving a magic wand, to rehouse great numbers of people, and a Labour Government would find itself faced by the same practical difficulties that have hitherto hampered and, in great measure, must continue to hamper, both central and local administrations. Slum clearance is a costly process, and comparatively little can be done in that direction until home...

A graph G of order n and size m is edge-magic if there is a bijection l : V (G) ∪E(G) → [n+m] such that all sums l(a) + l(b) + l(ab), ab ∈ E(G), are the same. We present new lower and upper bounds on M(n), the maximum size of an edge-magic graph of order n, being the first to show an upper bound of the form M(n) ≤ (1 − ǫ) ( n 2 ) . Concrete estimates for ǫ can be obtained by knowing s(k, n), th...

During its first cycle of observations, the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescope has observed very high energy γ-rays from fife galactic objects: the Crab Nebula, the SNRs HESS J1813-178 and HESS J1834-087, the Galactic Center and the γ-ray binary LS I +61 303. After a short introduction to the MAGIC telescope and the data analysis procedure, the results of these fife...

The lack of reference aromatic systems in the realm of inorganic aromatic compounds makes the evaluation of aromaticity in all-metal and semimetal clusters a difficult task. To date, calculation of nucleus-independent chemical shifts (NICS) has been the most widely used method to discuss aromaticity in these systems. In the first part of this work, we briefly review our previous studies, showin...