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to the TOA forcing and push the system closer to the 3 °C cumulative warming (since 1850s), which is a likely threshold for unprecedented climate change 95 . If on the other hand, the immediate target for control shifts entirely to BC (owing to its health impacts) without a reduction in non-BC aerosols

-coil array in brain imaging. With an array of five coils double-oblique heart images were obtained in one-third of conventional scan time. Magn Reson Med 42:952-962, 1999. 1999 Wiley-Liss, Inc. Key words: MRI; sensitivity encoding; SENSE; fast imaging; receiver coil array Among today's many medical

A general procedure which defines a partial ordering of cyclic permutations induced by continuous maps is known for constructing immediate successors to a cycle. We expound on this procedure in terms of labelled digraphs and characteristic polynomials then apply this study to period doubling

En termes generals, l’objectiu d’aquest treball és estudiar el problema ∆, (o problema grau-nombre de vèrtexs) per al cas de digrafs de doble pas. Un digraf és una xarxa constituïda per vèrtexs i arestes dirigides (anomenades arcs). En el cas dels grafs, les arestes no tenen direcció. Un digraf de doble pas consta de vèrtexs i un conjunt d’arcs de la forma , + i , + , amb i enters positius anomenats “passos”, és a dir, que existeixen enllaços des del vèrtex cap els vèrtexs + i + (les operacions s’han d’entendre sempre en mòdul ). Aquest digraf es denota El diàmetre d’un graf és la mínima distància possible que hi ha entre dos dels vèrtexs més allunyats entre si. En el diàmetre d’un digraf hem de tenir en compte que els arcs tenen direcció. La distància unilateral en un digraf és el mínim entre la distància en el digraf i en el digraf convers (obtingut canviant totes les direccions dels arcs). El problema ∆, ha estat molt estudiat en grafs i en digrafs, però no en el cas dels digrafs de doble pas considerant el diàmetre unilateral. El problema consisteix a trobar el mínim diàmetre unilateral ∗ en digrafs de doble pas, per a un nombre de vèrtexs i el grau ∆ = 2 donats, és a dir, trobar quins són els dos passos d’un digraf de doble pas que fan que el diàmetre unilateral ∗ sigui mínim per a aquests nombre de vèrtexs i grau.

A Threshold Circuit consists of an acyclic digraph of unbounded fanin, where each node computes a threshold function or its negation. This paper investigates the computational power of Threshold Circuits. A surprising relationship is uncovered between Threshold Circuits and another class

the classes of m-linked, m-ordered and strongly m-connected digraphs. First, we give sharp minimum semi-degree conditions for H-linkedness, extending results of Kühn and Osthus on m-linked and m-ordered digraphs. It is known that the minimum degree threshold for an undirected graph to be H-linked depends

of reset words for A is called the reset threshold of A. In 1964 Čern´y [2] constructed for each n> 1 a synchronizing automaton Cn with n states whose reset length is (n − 1) 2. Soon after that he conjectured that these automata represent the worst possible case, that is, every synchronizing automaton

Abstract. Let n be sufficiently large and suppose that G is a digraph on n vertices where every vertex has in- and outdegree at least n/2. We show that G contains every orientation of a Hamilton cycle except, possibly, the antidirected one. The antidirected case was settled by DeBiasio and Molla

to be in lexicographical order. We show that this condition is much too strong. Hence, we can give several, different sets of n inequalities. We think that this stronger result can be very important with respect to structural insights about the sets of digraph sequences for example in the context of threshold sequences