2,501,578 research outputs found

    The expressive power of modal logic with inclusion atoms

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    Modal inclusion logic is the extension of basic modal logic with inclusion atoms, and its semantics is defined on Kripke models with teams. A team of a Kripke model is just a subset of its domain. In this paper we give a complete characterisation for the expressive power of modal inclusion logic: a class of Kripke models with teams is definable in modal inclusion logic if and only if it is closed under k-bisimulation for some integer k, it is closed under unions, and it has the empty team property. We also prove that the same expressive power can be obtained by adding a single unary nonemptiness operator to modal logic. Furthermore, we establish an exponential lower bound for the size of the translation from modal inclusion logic to modal logic with the nonemptiness operator.Comment: In Proceedings GandALF 2015, arXiv:1509.0685

    OH+^+ emission from cometary knots in planetary nebulae

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    We model the molecular emission from cometary knots in planetary nebulae (PNe) using a combination of photoionization and photodissociation region (PDR) codes, for a range of central star properties and gas densities. Without the inclusion of ionizing extreme ultraviolet (EUV) radiation, our models require central star temperatures TT_* to be near the upper limit of the range investigated in order to match observed H2_2 and OH+^+ surface brightnesses consistent with observations - with the addition of EUV flux, our models reproduce observed OH+^+ surface brightnesses for T100kKT_* \ge 100 \, {\rm kK}. For T<80kKT_* < 80 \, {\rm kK}, the predicted OH+^+ surface brightness is much lower, consistent with the non-detection of this molecule in PNe with such central star temperatures. Our predicted level of H2_2 emission is somewhat weaker than commonly observed in PNe, which may be resolved by the inclusion of shock heating or fluorescence due to UV photons. Some of our models also predict ArH+^+ and HeH+^+ rotational line emission above detection thresholds, despite neither molecule having been detected in PNe, although the inclusion of photodissociation by EUV photons, which is neglected by our models, would be expected to reduce their detectability.Comment: Accepted by MNRAS, 11 pages, 15 figures. Author accepted manuscript. Accepted on 24/04/18. Deposited on 27/04/1

    Susy Particles

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    Analysis of the SUSY spectrum in supergravity unified models is given under the naturalness criterion that the universal scalar mass (m0)(m_0) and the gluino mass (mg~)(m_{\tilde g}) satisfy the constraint m0,mg~m_0, m_{\tilde g} less than or equal to 1 TeV. The SUSY spectrum is analysed in four different scenarios: (1) minimal supergravity models ignoring proton decay from dimension five operators, (2) imposing proton stability constraint in supergravity models with SU(5) type embedding which allow proton decay via dimension five operators, (3) with inclusion of dark matter constraints in models of type (1), and (4) with inclusion of dark matter constraint in models of type (2). It is found that there is a very strong upper limit on the light chargino mass in models of type (4), i.e., the light chargino mass is less than or equals 120 GeV.Comment: 16 pages+ 6 figs(hard copies available on request

    POS tagging for German : how important is the right context?

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    Part-of-Speech tagging is generally performed by Markov models, based on bigram or trigram models. While Markov models have a strong concentration on the left context of a word, many languages require the inclusion of right context for correct disambiguation. We show for German that the best results are reached by a combination of left and right context. If only left context is available, then changing the direction of analysis and going from right to left improves the results. In a version of MBT (Daelemans et al., 1996) with default parameter settings, the inclusion of the right context improved POS tagging accuracy from 94.00% to 96.08%, thus corroborating our hypothesis. The version with optimized parameters reaches 96.73%

    Mean-field limit for collective behavior models with sharp sensitivity regions

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    We rigorously show the mean-field limit for a large class of swarming individual based models with local sharp sensitivity regions. For instance, these models include nonlocal repulsive-attractive forces locally averaged over sharp vision cones and Cucker-Smale interactions with discontinuous communication weights. We construct global-in-time defined notion of solutions through a differential inclusion system corresponding to the particle descriptions. We estimate the error between the solutions to the differential inclusion system and weak solutions to the expected limiting kinetic equation by employing tools from optimal transport theory. Quantitative bounds on the expansion of the 1-Wasserstein distance along flows based on a weak-strong stability estimate are obtained. We also provide different examples of realistic sensitivity sets satisfying the assumptions of our main results

    Political Interest, Cognitive Ability and Personality - Determinants of Voter Turnout in Britain

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    This paper uses longitudinal data from the National Cohort Development Study (NCDS) to investigate the determinants of voter turnout in the 1997 British General Election. It introduces measures of cognitive ability and personality into models of electoral participation and finds that firstly, their inclusion reduces the impact of education and secondly, that standard turnout models may be biased by the inclusion of the much used “interest in politics” measure. A bivariate probit model of turnout and interest then shows that individuals with high ability, an aggressive personality and a sense of civic duty are more likely to both turn out to vote and to have an interest in politics.Turnout, Education, Ability, Personality
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