Universal Free Choice from Concessive Copular Conditionals in Tibetan

I describe the expression of free choice in Tibetan, which involves the combination of a wh-word, copula, conditional morphology, and a scalar ‘even’ particle. I demonstrate that the conventional semantics of these ingredients successfully combine to derive universal free choice meaning. This motivates a new approach to the compositional semantics of universal free choice, which does not prescribe its universal force. This quantificational force is parasitic on the modal/temporal operator which is restricted by the conditional; the scalar ‘even’ particle then ensures that the conditional restricts a necessity modal.

Probabilistic Strategy Logic

We introduce Probabilistic Strategy Logic, an extension of Strategy Logic for stochastic systems. The logic has probabilistic terms that allow it to express many standard solution concepts, such as Nash equilibria in randomised strategies, as well as constraints on probabilities, such as independence. We study the model-checking problem for agents with perfect- and imperfect-recall. The former is undecidable, while the latter is decidable in space exponential in the system and triple-exponential in the formula. We identify a natural fragment of the logic, in which every temporal operator is immediately preceded by a probabilistic operator, and show that it is decidable in space exponential in the system and the formula, and double-exponential in the nesting depth of the probabilistic terms. Taking a fixed nesting depth, this gives a fragment that still captures many standard solution concepts, and is decidable in exponential space.

Quirky Quantifiers: Optimal Models and Complexity of Computation Tree Logic

The satisfiability problem of the branching time logic CTL is studied in terms of computational complexity. Tight upper and lower bounds are provided for each temporal operator fragment. In parallel, the minimal model size is studied with a suitable notion of minimality. Thirdly, flat CTL is investigated, i.e., formulas with very low temporal operator nesting depth. A sharp dichotomy is shown in terms of complexity and minimal models: Temporal depth one has low expressive power, while temporal depth two is equivalent to full CTL.

Temporal Data Management and Processing with Column Oriented NoSQL Databases

This article introduces how temporal data can be maintained and processed by utilizing Column-oriented NoSQL databases (CoNoSQLDBs). Although each column in a CoNoSQLDB can store multiple data versions with their corresponded timestamps, its implicit temporal interval representation can cause wrong or misleading results during temporal query processing. In consequence, the original table representation supported by CoNoSQLDBs is not suitable for storing temporal data. To maintain the temporal data in the CoNoSQLDB tables, two alternative table representations can be adopted, namely, explicit history representation (EHR) and tuple time-stamping representation (TTR) in which each tuple (data version) has an explicit temporal interval. For processing TTR, the temporal relational algebra is extended to TTRO operator model with minor modifications. For processing EHR, a novel temporal operator model called CTO is proposed. Both TTRO and CTO contain eight temporal data operators, namely, Union, Difference, Intersection, Project, Filter, Cartesian product, Theta-Join and Group by with a set of aggregation functions, such as SUM, AVG, MAX and etc. Moreover, the authors implement each temporal operator by utilizing MapReduce framework to indicate which temporal operator model is more suitable for temporal data processing in the context of CoNoSQLDBs.

Some remarks on the semantics of ir + Infinitive in European Portuguese

This paper deals with the semantics of the European Portuguese structure ir + Infinitive, in particular when it occurs with the Pret©rito Perfeito (a terminative past tense) and the Presente do Indicativo (Simple Present). We will argue for the hypothesis that, indeed, in this language there are two different semantic configurations behind the ir + Infinitive sequence. In fact, we will begin describing a first reading in which ir seems to retain most of its basic lexical properties, imposing strong restrictions to the situations that can combine with it, concerning particularly their aspectual profile and the presence or absence of the agentive feature; then, we will explore a second interpretation in which ir behaves like a pure temporal operator of futurity, exhibiting the characteristics of a semi-auxiliary and imposing no relevant constraints to the eventualities that co-occur in the whole structure.

Motion-detecting mechanisms: Dual input devices?

Displacement thresholds for luminance step edges were measured for a wide range of contrasts and mean luminances. Thresholds for extended edges (longer than about 0.5°) are determined not by contrast but rather by the amplitude (Lmax-Lmin) of the luminance change produced by the displacement. Arguing from the standpoint of the Marr-Ullman model of movement detection, we had expected that thresholds might be jointly determined by both contrast and amplitude. Using a range of edges of different lengths, we found that differential effects of luminance and contrast can be revealed: for short edges (less than about 0.5°) thresholds are influenced by both amplitude and contrast, while for more extensive edges only amplitude has an influence. The results are consistent with the properties of a mechanism that has two separate inputs, one from a spatial operator that is contrast-dependent and one from a temporal operator that is amplitude-dependent. The spatial operator is markedly sensitive to changes in edge extent, the temporal operator much less so. The output of the spatial operator saturates early as a function of contrast.