4,692 research outputs found
Common adversaries form alliances: modelling complex networks via anti-transitivity
Anti-transitivity captures the notion that enemies of enemies are friends,
and arises naturally in the study of adversaries in social networks and in the
study of conflicting nation states or organizations. We present a simplified,
evolutionary model for anti-transitivity influencing link formation in complex
networks, and analyze the model's network dynamics. The Iterated Local
Anti-Transitivity (or ILAT) model creates anti-clone nodes in each time-step,
and joins anti-clones to the parent node's non-neighbor set. The graphs
generated by ILAT exhibit familiar properties of complex networks such as
densification, short distances (bounded by absolute constants), and bad
spectral expansion. We determine the cop and domination number for graphs
generated by ILAT, and finish with an analysis of their clustering
coefficients. We interpret these results within the context of real-world
complex networks and present open problems
The phylogenetic position of Dinogeophilus and a new evolutionary framework for the smallest epimorphic centipedes (Chilopoda: Epimorpha)
Searches for exotic physics at CMS
A review of the searches for new physics at the CMS experiment is presented. The latest results exploiting all the data collected in 2012, corresponding to 19.6 fb−1 of luminosity, are summarized. A broad range of final states and models of new physics is investigated. No statistically significant evidence of new physics has been found
A soja no Brasil: história e estatística.
Origem e distribuicao no mundo; Introducao e primeiras experiencias no Brasil; Evolucao da producao; Destino da producao; Capacidade de processamento; Portos de embarque; Meios de transporte; Precos recebidos pelos produtores; Custos de producao.bitstream/item/23236/1/Doc21.pd
The capture time of grids
We consider the game of Cops and Robber played on the Cartesian product of
two trees. Assuming the players play perfectly, it is shown that if there are
two cops in the game, then the length of the game (known as the 2-capture time
of the graph) is equal to half the diameter of the graph. In particular, the
2-capture time of the m x n grid is proved to be floor ((m+n-2)/2).Comment: 7 page
Extração de DNA genômico de cereais de inverno na Embrapa Trigo.
bitstream/CNPT-2010/40600/1/p-co235.pd
The Cop Number of the One-Cop-Moves Game on Planar Graphs
Cops and robbers is a vertex-pursuit game played on graphs. In the classical
cops-and-robbers game, a set of cops and a robber occupy the vertices of the
graph and move alternately along the graph's edges with perfect information
about each other's positions. If a cop eventually occupies the same vertex as
the robber, then the cops win; the robber wins if she can indefinitely evade
capture. Aigner and Frommer established that in every connected planar graph,
three cops are sufficient to capture a single robber. In this paper, we
consider a recently studied variant of the cops-and-robbers game, alternately
called the one-active-cop game, one-cop-moves game or the lazy-cops-and-robbers
game, where at most one cop can move during any round. We show that Aigner and
Frommer's result does not generalise to this game variant by constructing a
connected planar graph on which a robber can indefinitely evade three cops in
the one-cop-moves game. This answers a question recently raised by Sullivan,
Townsend and Werzanski.Comment: 32 page
NP-Completeness Results for Graph Burning on Geometric Graphs
Graph burning runs on discrete time steps. The aim is to burn all the
vertices in a given graph in the least number of time steps. This number is
known to be the burning number of the graph. The spread of social influence, an
alarm, or a social contagion can be modeled using graph burning. The less the
burning number, the faster the spread.
Optimal burning of general graphs is NP-Hard. There is a 3-approximation
algorithm to burn general graphs where as better approximation factors are
there for many sub classes. Here we study burning of grids; provide a lower
bound for burning arbitrary grids and a 2-approximation algorithm for burning
square grids. On the other hand, burning path forests, spider graphs, and trees
with maximum degree three is already known to be NP-Complete. In this article
we show burning problem to be NP-Complete on connected interval graphs,
permutation graphs and several other geometric graph classes as corollaries.Comment: 17 pages, 5 figure
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