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891.
892.
In this work we develop goal-directed deduction methods for the implicational fragment of several modal logics. We give sound and complete procedures for strict implication of K, T, K4, S4, K5, K45, KB, KTB, S5, G and for some intuitionistic variants. In order to achieve a uniform and concise presentation, we first develop our methods in the framework of Labelled Deductive Systems [Gabbay 96]. The proof systems we present are strongly analytical and satisfy a basic property of cut admissibility. We then show that for most of the systems under consideration the labelling mechanism can be avoided by choosing an appropriate way of structuring theories. One peculiar feature of our proof systems is the use of restart rules which allow to re-ask the original goal of a deduction. In case of K, K4, S4 and G, we can eliminate such a rule, without loosing completeness. In all the other cases, by dropping such a rule, we get an intuitionistic variant of each system. The present results are part of a larger project of a goal directed proof theory for non-classical logics; the purpose of this project is to show that most implicational logics stem from slight variations of a unique deduction method, and from different ways of structuring theories. Moreover, the proof systems we present follow the logic programming style of deduction and seem promising for proof search [Gabbay and Reyle 84, Miller et al. 91]. 相似文献
893.
In continuation of our study of HST, Hrbaek set theory (a nonstandard set theory which includes, in particular, the ZFC Replacement and Separation schemata in the st--language, and Saturation for well-orderable families of internal sets), we consider the problem of existence of elementary extensions of inner "external" subclasses of the HST universe.We show that, given a standard cardinal , any set R * generates an "internal" class S(R) of all sets standard relatively to elements of R, and an "external" class L[S(R)] of all sets constructible (in a sense close to the Gödel constructibility) from sets in S(R). We prove that under some mild saturation-like requirements for R the class L[S(R)] models a certain -version of HST including the principle of +-saturation; moreover, in this case L[S(R)] is an elementary extension of L[S(R)] in the st--language whenever sets R R satisfy the requirements. 相似文献
894.
Studia Logica - Using two distinct membership symbols makes possible to base set theory on one general axiom schema of comprehension. Is the resulting system consistent? Can set theory and... 相似文献
895.
Barbara Hanley Marc J. Tassé Michael G. Aman Pamela Pace 《Journal of child and family studies》1998,7(1):69-77
Social support systems can have either a beneficial or adverse effect when a family faces stress. Hence, support perceived by family members is an important construct. We studied the psychometric properties of the Family Support Scale (FSS) with a sample of 244 low-income families of children in a Head Start program, and we conducted an exploratory factor analysis with the scale. We obtained a 5-factor solution for the FSS when assessing the family support of low-income families. The internal consistency and test-retest reliability were moderately high for the 5 proposed subscales. The factor structure obtained may prove more valid for Head Start families than structures from previous studies, although there is still a need for further psychometric study of the FSS. 相似文献
896.
Substructural logics on display 总被引:1,自引:0,他引:1
897.
Medical semiotics in the 18th century was more than a premodern form of diagnosis. Its structure allowed for the combination of empirically proven rules of instruction with the theoretical knowledge of the new sciences, employing the relation between the sign and the signified. 相似文献
898.
U. Tnne A. J. Hiltunen K. Engelbrektsson H. Bjrvell B. Vikander S. Borg 《Personality and individual differences》1998,24(6):797-804
The present study applied Karolinska Scales of Personality (KSP) to study (i) if patients with benzodiazepine dependence have a characteristic personality profile, (ii) if the personality characteristics in patients with benzodiazepine dependence differ from those of polydrug users and normal controls, (iii) if differences in treatment outcome existed between the groups, and (iv) if the possible difference in treatment outcome was associated with any particular personality characteristic shown by the patients. The personality characteristics of primary benzodiazepine dependent patients (BDZ) and a group of polydrug users (MIX) were studied initially (during the first week in project as an inpatient) and approximately one year after drug discontinuation, and a comparison was made with healthy controls on both test occasions. The results showed that the personality of both groups of patients differed significantly from the Controls in the following characteristics: Detachment, Socialization, Somatic Anxiety, Muscular Tension, Psychic Anxiety, and Psychasthenia. Significant differences existed between the polydrug and benzodiazepine users in Somatic and Psychic Anxiety as well as in Socialization. The MIX group differed significantly from the BDZ group and from the Controls in Suspicion. Results of treatment outcome indicated that the benzodiazepine dependent patients were significantly more successful in quitting their drug use compared to polydrug users. Further, the results demonstrated that patients scoring high in the investigated personality characteristics are those who fail the treatment goal of quitting their drug use, especially the patients with a high level of anxiety and detachment. 相似文献
899.
在内隐学习条件下任务难度对于判断准确率的影响 总被引:3,自引:0,他引:3
本研究利用自行设计的复杂规则产生出不同难度的任务系统,进而通过实验阐明了内隐学习的三个特征;(一)在任务难度极大的情况下,内隐学习并不发挥作用;(二)在任务难度降低到一定程度的时间,内隐学习开始发挥作用,这仿佛是一个“阈限”;(三)随着任务难度逐渐降低,内隐学习的效率也随着提高,但是最科停止在一个较高的水平而再继续上升,可以间接推断,内隐学习获得了样例的具体信息。 相似文献
900.
Nadya A. Fouad Romila SinghKevin Cappaert Wen-hsin ChangMin Wan 《Journal of Vocational Behavior》2016
The current research examined differences between women engineers who persisted in an engineering career versus those who left engineering using a combination of two prominent theories of career change: social cognitive career theory (SCCT, Lent, Brown & Hackett, 1994; 2002) and integrated model of career change (Rhodes & Doering, 1983). The two groups of women did not differ in three domains of self-confidence or outcome expectations (engineering tasks, navigating organizational climate, or multiple roles), in vocational interests, or in workplace barriers. Women who continue in engineering do differ from those who leave in their experience of workplace supports and their levels of occupational commitment. Engineering turnover intentions and occupational commitment emerged as the two key variables that explained 33.4% of the variance in persistence in engineering careers. We discuss the implications of the results in terms of theoretical development and practical implications for organizations. 相似文献