4,209 research outputs found
The Vampire and the FOOL
This paper presents new features recently implemented in the theorem prover
Vampire, namely support for first-order logic with a first class boolean sort
(FOOL) and polymorphic arrays. In addition to having a first class boolean
sort, FOOL also contains if-then-else and let-in expressions. We argue that
presented extensions facilitate reasoning-based program analysis, both by
increasing the expressivity of first-order reasoners and by gains in
efficiency
Ocorrência do míldio da videira em diferentes épocas de podas em Petrolina - PE.
Suplemento. Edição dos Resumos do 44 Congresso Brasileiro de Fitopatologia, Bento Gonçalves, ago. 2011
On multigraded generalizations of Kirillov-Reshetikhin modules
We study the category of Z^l-graded modules with finite-dimensional graded
pieces for certain Z+^l-graded Lie algebras. We also consider certain Serre
subcategories with finitely many isomorphism classes of simple objects. We
construct projective resolutions for the simple modules in these categories and
compute the Ext groups between simple modules. We show that the projective
covers of the simple modules in these Serre subcategories can be regarded as
multigraded generalizations of Kirillov-Reshetikhin modules and give a
recursive formula for computing their graded characters
Microstructure identification via detrended fluctuation analysis of ultrasound signals
We describe an algorithm for simulating ultrasound propagation in random
one-dimensional media, mimicking different microstructures by choosing physical
properties such as domain sizes and mass densities from probability
distributions. By combining a detrended fluctuation analysis (DFA) of the
simulated ultrasound signals with tools from the pattern-recognition
literature, we build a Gaussian classifier which is able to associate each
ultrasound signal with its corresponding microstructure with a very high
success rate. Furthermore, we also show that DFA data can be used to train a
multilayer perceptron which estimates numerical values of physical properties
associated with distinct microstructures.Comment: Submitted to Phys. Rev.
Hierarchic Superposition Revisited
Many applications of automated deduction require reasoning in first-order
logic modulo background theories, in particular some form of integer
arithmetic. A major unsolved research challenge is to design theorem provers
that are "reasonably complete" even in the presence of free function symbols
ranging into a background theory sort. The hierarchic superposition calculus of
Bachmair, Ganzinger, and Waldmann already supports such symbols, but, as we
demonstrate, not optimally. This paper aims to rectify the situation by
introducing a novel form of clause abstraction, a core component in the
hierarchic superposition calculus for transforming clauses into a form needed
for internal operation. We argue for the benefits of the resulting calculus and
provide two new completeness results: one for the fragment where all
background-sorted terms are ground and another one for a special case of linear
(integer or rational) arithmetic as a background theory
Structural properties of crumpled cream layers
The cream layer is a complex heterogeneous material of biological origin
which forms spontaneously at the air-milk interface. Here, it is studied the
crumpling of a single cream layer packing under its own weight at room
temperature in three-dimensional space. The structure obtained in these
circumstances has low volume fraction and anomalous fractal dimensions. Direct
means and noninvasive NMR imaging technique are used to investigate the
internal and external structure of these systems.Comment: 9 pages, 4 figures, accepted in J. Phys. D: Appl. Phy
Approaching the Coverability Problem Continuously
The coverability problem for Petri nets plays a central role in the
verification of concurrent shared-memory programs. However, its high
EXPSPACE-complete complexity poses a challenge when encountered in real-world
instances. In this paper, we develop a new approach to this problem which is
primarily based on applying forward coverability in continuous Petri nets as a
pruning criterion inside a backward coverability framework. A cornerstone of
our approach is the efficient encoding of a recently developed polynomial-time
algorithm for reachability in continuous Petri nets into SMT. We demonstrate
the effectiveness of our approach on standard benchmarks from the literature,
which shows that our approach decides significantly more instances than any
existing tool and is in addition often much faster, in particular on large
instances.Comment: 18 pages, 4 figure
Scattering map for two black holes
We study the motion of light in the gravitational field of two Schwarzschild
black holes, making the approximation that they are far apart, so that the
motion of light rays in the neighborhood of one black hole can be considered to
be the result of the action of each black hole separately. Using this
approximation, the dynamics is reduced to a 2-dimensional map, which we study
both numerically and analytically. The map is found to be chaotic, with a
fractal basin boundary separating the possible outcomes of the orbits (escape
or falling into one of the black holes). In the limit of large separation
distances, the basin boundary becomes a self-similar Cantor set, and we find
that the box-counting dimension decays slowly with the separation distance,
following a logarithmic decay law.Comment: 20 pages, 5 figures, uses REVTE
Ganho genético em potencial produtivo do arroz irrigado no Rio Grande do Sul, após o lançamento da cultivar BR-IRGA 409.
Este trabalho teve como objetivo estimar os ganhos genéticos em rendimento de grãos nos últimos 30 anos, ou a partir do lançamento da cultivar BR-IRGA 409, no estado do Rio Grande do Sul, com base no desempenho de cultivares representativas lançadas pela pesquisa
Análise genética entre acessos de Oenocarpus mapora (Arecaceae) de hábito cespitoso e solitário.
A bacaby ou Oenocarpus mapora é uma palmeira considerada potencial para a domesticação devido às suas características comerciais de seu fruto e palmito. A espécie tem hábito predominantemente cespitoso, mas palmeiras de hábito solitário já foram descritas. O banco de germoplasma (BAG) do complexo Oenocarpus/Jessenia da Embrapa Amazônia Oriental possui em seu acervo uma amostra de materiais do tipo solitário de O. mapora coletados no noroeste paraense. Para veriicar a diversidade genética desse grupo no BAG e sua proximidade genética com materiais de hábito cespitoso, foram utilizados 18 indivíduos do tipo solitário para serem comparados com 1γ indivíduos do tipo cespitoso coletados em Itacoatiara (Aε) e oito coletados em Parintins (Aε), por meio de genotipagem com cinco locos microssatélites. A análise descritiva mostrou que há variabilidade genética dentro do grupo do tipo solitário, com H E = 0,7λ, variação que foi maior que a dos grupos de hábito cespitoso. A análise com AεOVA demonstrou grande diferenciação entre os grupos, com γβ,γη% de variação genética entre grupos. A distância genética par a par com base em FST mostrou que houve diferença significativa entre os grupos, e que o grupo do tipo solitário teve mais proximidade genética com um dos grupos do tipo cespitoso, do que entre os grupos do tipo cespitoso, indicando que o material pode ser utilizado em programas de melhoramento
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