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The completeness of linear logic for Petri net models   总被引:1,自引:0,他引:1  
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Intermediate prepositional logics we consider here describe the setI() of regular informational types introduced by Yu. T. Medvedev [7]. He showed thatI() is a Heyting algebra. This algebra gives rise to the logic of infinite problems from [13] denoted here asLM 1. Some other definitions of negation inI() lead to logicsLM n (n ). We study inclusions between these and other systems, proveLM n to be non-finitely axiomatizable (n ) and recursively axiomatizable (n < ). We also show that formulas in one variable do not separateLM from Heyting's logicH, andLM n (n < ) from Scott's logic (H+S).  相似文献   

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Recent years have seen considerable interest in procedures for computing finite models of first-order logic specifications. One of the major paradigms, MACE-style model building, is based on reducing model search to a sequence of propositional satisfiability problems and applying (efficient) SAT solvers to them. A problem with this method is that it does not scale well because the propositional formulas to be considered may become very large.We propose instead to reduce model search to a sequence of satisfiability problems consisting of function-free first-order clause sets, and to apply (efficient) theorem provers capable of deciding such problems. The main appeal of this method is that first-order clause sets grow more slowly than their propositional counterparts, thus allowing for more space efficient reasoning.In this paper we describe our proposed reduction in detail and discuss how it is integrated into the Darwin prover, our implementation of the Model Evolution calculus. The results are general, however, as our approach can be used in principle with any system that decides the satisfiability of function-free first-order clause sets.To demonstrate its practical feasibility, we tested our approach on all satisfiable problems from the TPTP library. Our methods can solve a significant subset of these problems, which overlaps but is not included in the subset of problems solvable by state-of-the-art finite model builders such as Paradox and Mace4.  相似文献   

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Carl J. Posy 《Topoi》1982,1(1-2):30-43
IPC, the intuitionistic predicate calculus, has the property
  1. Vc(Γ?A c /x) ? Γ??xA.Furthermore, for certain important Γ, IPC has the converse property
  2. Γ??xA ? Vc(Γ?A c /x).
  3. may be given up in various ways, corresponding to different philosophic intuitions and yielding different systems of intuitionistic free logic. The present paper proves the strong completeness of several of these with respect to Kripke style semantics. It also shows that giving up (i) need not force us to abandon the analogue of (ii).
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The basic assumptions of psychotherapy must necessarily reflect the cultural orientations and dilemmas of the western societies, and historical periods, in which these originated. This paper considers how the racialised biases of that period, namely, the era of European domination built upon the conquest, colonisation and enslavement of non‐European peoples, may linger in psychotherapeutic training and practice today. This not only limits the potential usefulness of the discipline in the multicultural populations of the west, but also risks it being read as covert neo‐colonialism in the ‘non‐west’. In a world that ever more clearly demonstrates the human costs of prejudice psychotherapists in general, and Jungians in particular, might wish to consider how, wittingly or otherwise, they maintain prejudiced ways of thinking. This paper examines material from the author's professional and personal experience, using literature that lies outside the specifically Jungian canon, to expose how such bias might work.  相似文献   

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Models are sometimes developed on the premise that there are no differences between two or more conditions regardless of experimental manipulation. This article argues that unless a very sensitive experiment (or series of experiments) was conducted, such conclusions are often premature. Design and statistical factors such as alpha level, variability, sample size, and treatment effect are all determinants of the sensitivity of the experiment. It is sometimes the case that an experiment produces differences between means and yet the null hypothesis is not rejected because of high variability within experimental conditions or because too few subjects were used. Unless the probability of detecting a difference between groups is known, it would seem unwise to conclude that no difference exists. Judgment on the model should be suspended. Examples are taken from the mass-spring and pulse-step models fro voluntary movement control to illustrate the problem.  相似文献   

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We present an hierarchical Bayes approach to modeling parameter heterogeneity in generalized linear models. The model assumes that there are relevant subpopulations and that within each subpopulation the individual-level regression coefficients have a multivariate normal distribution. However, class membership is not known a priori, so the heterogeneity in the regression coefficients becomes a finite mixture of normal distributions. This approach combines the flexibility of semiparametric, latent class models that assume common parameters for each sub-population and the parsimony of random effects models that assume normal distributions for the regression parameters. The number of subpopulations is selected to maximize the posterior probability of the model being true. Simulations are presented which document the performance of the methodology for synthetic data with known heterogeneity and number of sub-populations. An application is presented concerning preferences for various aspects of personal computers.  相似文献   

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This report describes some recent examinations of the ability of aphasic patients to construct syntactically governed dependency relations in real time. The data show that Wernicke's patients can link the elements of dependency relations in the same way as neurologically intact subjects, even for sentences that they do not understand. Broca's patients, by contrast, are shown to be unable to create such links, even for sentences that they do understand. These data underline the isolability of this stage of syntactic analysis and they suggest that comprehension limitations statable in syntactic terms can be traced to changes in cortically localizable processing resources.  相似文献   

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It is assumed that confi dentiality is not one singular ethical entity but a conglomerate of quite different issues depending upon clinical context and the sector of information sharing at stake. The focus here is on how to think psychoanalytically about requests for information from third parties (payers, courts, public security). Defi ning confi dentiality as a promise to 'never tell anything' outside of the relationship omits evaluation of the impact of the third's listening on the combined freedom of thought and freedom of speech in analyst and analysand. Circulation of information outside the dyad need not be toxic, need not disrupt the analytic couple's openness to new meaning. Key to contamination and inhibition of analytic work is whether or not disclosure serves an analytic end. Current defense of confi dentiality relies heavily on the models of protection of privacy and professional secrecy, which, though useful and relevant, fail to encompass the transitional, intersubjective space engendered by the analytic process. Suggestions are made for alternate sources of paradigms better suited to represent the latter. Offered for discussion is a draft of a confi dentiality policy with respect to third parties that is informed by psychoanalytic theory and clinical practice rather than by local legal jurisdiction or original disciplines ethics codes.  相似文献   

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Methods developed by Bernbach [1966] and Millward [1969] permit increased generality in analyses of identifiability. Matrix equations are presented that solve part of the identifiability problem for a class of Markov models. Results of several earlier analyses are shown to involve special cases of the equations developed here. And it is shown that a general four-state chain has the same parameter space as an all-or-none model if and only if its representation with an observable absorbing state is lumpable into a Markov chain with three states.This research was supported by the U.S. Public Health Service under Grant MH-12717 to Indiana University and Grant GM-1231 to the University of Michigan.Now at the University of Texas, Austin.  相似文献   

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The effect of task instructions on taste adaptation was investigated in two experiments. In the first experiment, three groups of subjects received a 3-min flow of salt solution, over the anterior dorsal tongue surface and periodically gave magnitude estimates of its intensity. Each group had previously received different instructions suggesting the appropriate outcome of the adaptation experiment. Not all subjects showed adaptation, and the instructions had no significant differential effects. In the second experiment, subjects who were practiced in judging pulsatile taste stimuli were instructed to rate the intensity of a continuous salt stimulus as it disappeared, but this produced no increased adaptation. Several possible hypotheses are presented to account for this repeatedly observed failure of many subjects to completely adapt to taste stimuli.  相似文献   

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Bilateral electrolytic lesions in the periamygdaloid piriform cortex of female albino rats produced marked disruptive effects on the acquisition of active avoidance responses in a 1-way as well as a 2-way test situation, significantly impaired passive avoidance behavior, and inhibited feeding in a novel environment. Lesions in each of the 6 major subdivisions of the amygdala (cortical, medial, central, intercalated, lateral, and basolateral nuclei) consistently produced facilitatory effects on active avoidance behavior in 1-way as 2-way situations. Passive avoidance behavior was impaired in animals with lesions in the central, intercalated, and basolateral nuclei. Damage to the anterior amygdaloid area or the the nuclei of the lateral olfactory tract did not reliably affect active or passive avoidance behavior.  相似文献   

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