Beth Semantics and Labelled Deduction for Intuitionistic Sentential Calculus with Identity

International audienceIn this paper we consider the Intuitionistic Sentential Calculus with Suszko’s Identity (ISCI). After recalling the basic concepts of the logic and its associated Hilbert proof system, we introduce a newsound and complete class of models for ISCI which can be viewed as algebraic counterparts (and extensions) of sheaf-theoretic topological models of intuitionistic logic. We use this new class of models, called Beth semantics for ISCI, to derive a first labelled sequent calculus and show its adequacy w.r.t. the standard Hilbert axiomatization of ISCI. This labelled proof system, like all other current proof systems that we know of, does not enjoy the subformula property, which is problematic for achieving termination. We therefore introduce a second labelled sequent calculus in which the standard rules for identity are replaced with new special rules and show that this second calculus admits cut-elimination. Finally, using a key regularity property of the forcing relation in Beth models, we show that the eigenvariable condition can be dropped, thus leading to the termination and decidability results

A separation logic with histories of epistemic actions as resources

International audienceWe propose a separation logic where resources are histories (sequences) of epistemic actions so that resource update means concatenation of histories and resource decomposition means splitting of histories. This separation logic, called AMHSL, allows us to reason about the past: does what is true now depend on what was true in the past, before certain actions were executed? We show that the multiplicative connectives can be eliminated from a logical language with also epistemic and action model modalities, if the horizon of epistemic actions is bounded

An Epistemic Separation Logic with Action Models

International audienceIn this paper we generalize the dynamic aspects of Public Announcement Separation Logic (PASL), by defining Epistemic Separation Logic with Action Models (ESLAM), in which we replace public announcements with action models, motivated by their ability to model factual change, and instances of a more nuanced, private communication

Variation in strategies used by university students to learn English: Conclusions from a study

The present paper investigates the relationships between language learning strategies and their determinants, such as learners’ gender, their area of studies, and personality traits. It describes a study conducted on a group of 199 students of the Faculty of Social Sciences at Adam Mickiewicz University in Poznań. The results of the study indicate that a number of statistically significant relationships exist between strategy use and other individual variables, e.g. gender, level of proficiency, or learners’ area of studies. Moreover, the authors of the study make an attempt to identify and characterise students’ profiles in terms of their personal characteristics and strategic preferences so asto cast light on various paths to foreign language proficiency