A coffee with Jacques Rancière beneath the Acropolis

We met Jacques Rancière on Saturday, May 27, 2017, at the School of Fine Arts shortly before his speech at the B-Fest 6 International Anti-Authoritarian Festival, organized by Babylonia Journal, with a central slogan “We are ungovernable”. Rancière is among the most important European philosophers alive and his work does not need further introductions. In the cloudy morning of Sunday 28 May, we sat beneath the Acropolis to have a coffee with the philosopher. The transcript of our conversation reflects the vigor of thought and the passion of a truly democratic thinker

Datalog Rewritability of Disjunctive Datalog Programs and its Applications to Ontology Reasoning

We study the problem of rewriting a disjunctive datalog program into plain datalog. We show that a disjunctive program is rewritable if and only if it is equivalent to a linear disjunctive program, thus providing a novel characterisation of datalog rewritability. Motivated by this result, we propose weakly linear disjunctive datalog---a novel rule-based KR language that extends both datalog and linear disjunctive datalog and for which reasoning is tractable in data complexity. We then explore applications of weakly linear programs to ontology reasoning and propose a tractable extension of OWL 2 RL with disjunctive axioms. Our empirical results suggest that many non-Horn ontologies can be reduced to weakly linear programs and that query answering over such ontologies using a datalog engine is feasible in practice.Comment: 14 pages. To appear at AAAI-1

A Note on the Adoption of the Byzantine Models in Medieval Bulgaria (9th–10th Centuries). The Case with the Chrysorrhoas Collection

The paper aims at examining the first Slavic collection of homilies of John Chrysostom, called Zlatostruy (i.e. Chrysorrhoas or Golden Stream). The peculiarities of its content, compilation strategy and impact on the medieval Bulgarian literature, revealed in previous studies, allow us to extract features that are related to the flourishing of the 10th century Bulgarian literary tradition and the successful adoption of Byzantine models.Publication of English-language versions of the volumes of the yearly Studia Ceranea. Journal of the Waldemar Ceran Research Centre for the History and Culture of the Mediterranean Area and South-East Europe financed through contract no. 501/1/P-DUN/2017 from the funds of the Ministry of Science and Higher Education devoted to the promotion of scholarship

Combining Rewriting and Incremental Materialisation Maintenance for Datalog Programs with Equality

Materialisation precomputes all consequences of a set of facts and a datalog program so that queries can be evaluated directly (i.e., independently from the program). Rewriting optimises materialisation for datalog programs with equality by replacing all equal constants with a single representative; and incremental maintenance algorithms can efficiently update a materialisation for small changes in the input facts. Both techniques are critical to practical applicability of datalog systems; however, we are unaware of an approach that combines rewriting and incremental maintenance. In this paper we present the first such combination, and we show empirically that it can speed up updates by several orders of magnitude compared to using either rewriting or incremental maintenance in isolation.Comment: All proofs contained in the appendix. 7 pages + 4 pages appendix. 7 algorithms and one table with evaluation result

On pore-scale modeling and simulation of reactive transport in 3D geometries

Pore-scale modeling and simulation of reactive flow in porous media has a range of diverse applications, and poses a number of research challenges. It is known that the morphology of a porous medium has significant influence on the local flow rate, which can have a substantial impact on the rate of chemical reactions. While there are a large number of papers and software tools dedicated to simulating either fluid flow in 3D computerized tomography (CT) images or reactive flow using pore-network models, little attention to date has been focused on the pore-scale simulation of sorptive transport in 3D CT images, which is the specific focus of this paper. Here we first present an algorithm for the simulation of such reactive flows directly on images, which is implemented in a sophisticated software package. We then use this software to present numerical results in two resolved geometries, illustrating the importance of pore-scale simulation and the flexibility of our software package.Comment: 15 pages, 6 figure

Lawfare as a Form of Hybrid War: the case of Bulgaria; an Empirical View

This article is about the application of lawfare as a tool of a hybrid war. After analyzing the existing positions in the academic debate, a working definition of the latter is given; then the main theoretical postulates are operationalized as empirical indicators and finally, four cases of Russia's lawfare against Bulgaria are stated. It is argued that lawfare can be used to achieve the capture of the state, what eventually is a goal of every war, including the hybrid one and that such a capture is more probable in states which are former Russian satellites, where Russia indirectly can impact national legislative and decision making process

Limit Cycles of Perturbations of a Class of Quadratic Hamiltonian Vector Fields

We prove that in quadratic perturbations of generic Hamiltonian vector fields with two saddle points and one center there can appear at most two limit cycles. This bound is exact

VALERIY GERASIMOV AND DOCTRINE ON HYBRID WAR

Hybrid wars as a new generation of conflicts are largely discussed today. The purpose of this article is to analyze Gerasimov’s doctrine, by interpreting its main aspects. The analysis is based on original empirical research of his publications