A Characterization Result for Non-Distributive Logics

Recent published work has addressed the Shalqvist correspondence problem for non-distributive logics. The natural question that arises is to identify the fragment of first-order logic that corresponds to logics without distribution, lifting van Benthem's characterization result for modal logic to this new setting. Carrying out this project is the contribution of the present article. The article is intended as a demonstration and application of a project of reduction of non-distributive logics to (sorted) residuated modal logics. The reduction is an application of recent representation results by this author for normal lattice expansions and a generalization of a canonical and fully abstract translation of the language of substructural logics into the language of their companion sorted, residuated modal logics. The reduction of non-distributive logics to sorted modal logics makes the proof of a van Benthem characterization of non-distributive logics nearly effortless, by adapting and reusing existing results, demonstrating the usefulness and suitability of this approach in studying logics that may lack distribution

A Note on the history of Hellenistic Megara: Τhe date of the Antigonid garrison in Aegosthena

This paper presents a proposal for the date of the Antigonid military presence in Aegosthena near Megara, which is known only by a Megarian honorary decree for Boiotian Zoilos, the royal commander of the garrison (IG VII 1). The named king Demetrios in the inscription could be Poliorketes (306-284 BC) or his grandson, Demetrios II (239-229 BC). All the available evidences (philological, prosopographical, letters a.o.) are examined and the conclusion is that a date around 295-287 BC is the more preferable

A Note on the history of Hellenistic Megara: Τhe date of the Antigonid garrison in Aegosthena

This paper presents a proposal for the date of the Antigonid military presence in Aegosthena near Megara, which is known only by a Megarian honorary decree for Boiotian Zoilos, the royal commander of the garrison (IG VII 1). The named king Demetrios in the inscription could be Poliorketes (306-284 BC) or his grandson, Demetrios II (239-229 BC). All the available evidences (philological, prosopographical, letters a.o.) are examined and the conclusion is that a date around 295-287 BC is the more preferable

Reconciliation of Approaches to the Semantics of Logics without Distribution

This article contributes in that it clarifies and indeed completes an approach (initiated by Dunn and this author several years ago and again pursued by the present author over the last three years or so) to the relational semantics of logics that may lack distribution (Dunn's non-distributive gaggles). The approach uses sorted frames with an incidence relation on sorts (polarities), equipped with additional sorted relations, but, in the spirit of Occam's razor principle, it drops the extra assumptions made in the generalized Kripke frames approach, initiated by Gehrke, that the frames be separated and reduced (RS-frames). We show in this article that, despite rejecting the additional frame restrictions, all the main ideas and results of the RS-frames approach relating to the semantics of non-distributive logics are captured in this simpler framework. This contributes in unifying the research field, and, in an important sense, it complements and completes Dunn's gaggle theory project for the particular case of logics that may drop distribution

Why Grexit cannot save Greece (but staying in the Euro area might). LEQS Discussion Paper No. 123/2017 August 2017

Grexit was narrowly averted in summer 2015. Nevertheless, the view that Greece might be better off outside the Euro area has never really gone away. Moreover, although Marine Le Pen’s bid for the French presidency was frustrated in May 2017, in Italy a disparate coalition, encompassing Beppe Grillo’s Movimento Cinque Stelle as well as Matteo Salvini’s Lega Nord, has called for a referendum on exiting the Euro. In this context, our argument that Grexit cannot save Greece may be of some relevance to national debates elsewhere in Europe. The paper examines the case for Grexit by offering a detailed account of its likely effects. Its structure is as follows. Section 2 analyses the transition, with the two currencies (old and new) coexisting. Section 3 charts the challenges facing the Greek economy in the short term, after the new national currency has become legal tender. Section 4 assesses prospects in the medium term, with Grexit complete and the new currency drastically devalued. Section 5 reviews the underlying weaknesses of Greece’s growth regime and explains why these are unrelated to the nominal exchange rate. Section 6 discusses the conditions for an investment-led recovery, and shows why tackling them would be more difficult outside the Euro area. Section 7 sums up and concludes

On theoretical pricing of options with fuzzy estimators

AbstractIn this paper we present an application of a new method of constructing fuzzy estimators for the parameters of a given probability distribution function, using statistical data. This application belongs to the financial field and especially to the section of financial engineering. In financial markets there are great fluctuations, thus the element of vagueness and uncertainty is frequent. This application concerns Theoretical Pricing of Options and in particular the Black and Scholes Options Pricing formula. We make use of fuzzy estimators for the volatility of stock returns and we consider the stock price as a symmetric triangular fuzzy number. Furthermore we apply the Black and Scholes formula by using adaptive fuzzy numbers introduced by Thiagarajah et al. [K. Thiagarajah, S.S. Appadoo, A. Thavaneswaran, Option valuation model with adaptive fuzzy numbers, Computers and Mathematics with Applications 53 (2007) 831–841] for the stock price and the volatility and we replace the fuzzy volatility and the fuzzy stock price by possibilistic mean value. We refer to both cases of call and put option prices according to the Black & Scholes model and also analyze the results to Greek parameters. Finally, a numerical example is presented for both methods and a comparison is realized based on the results

SARS-CoV-2 Dissemination using a Network of the United States Counties

During 2020 and 2021, severe acute respiratory syndrome coron- avirus 2 (SARS-CoV-2) transmission has been increasing amongst the world’s population at an alarming rate. Reducing the spread of SARS-CoV-2 and other diseases that are spread in similar manners is paramount for public health of- ficials as they seek to effectively manage resources and potential population control measures such as social distancing and quarantines. By analyzing the United States’ county network structure, one can model and interdict poten- tial higher infection areas. County officials can provide targeted information, preparedness training, as well as increase testing in these areas. While these approaches may provide adequate countermeasures for localized areas, they are inadequate for the holistic United States. We solve this problem by col- lecting coronavirus disease 2019 (COVID-19) infections and deaths from the Center for Disease Control and Prevention and a network adjacency structure from the United States Census Bureau. Generalized network autoregressive (GNAR) time series models have been proposed as an efficient learning algorithm for networked datasets. This work fuses network science and operations research techniques to univariately model COVID-19 cases, deaths, and cur- rent survivors across the United States’ county network structure

Solving reward-collecting problems with UAVs: a comparison of online optimization and Q-learning

Uncrewed autonomous vehicles (UAVs) have made significant contributions to reconnaissance and surveillance missions in past US military campaigns. As the prevalence of UAVs increases, there has also been improvements in counter-UAV technology that makes it difficult for them to successfully obtain valuable intelligence within an area of interest. Hence, it has become important that modern UAVs can accomplish their missions while maximizing their chances of survival. In this work, we specifically study the problem of identifying a short path from a designated start to a goal, while collecting all rewards and avoiding adversaries that move randomly on the grid. We also provide a possible application of the framework in a military setting, that of autonomous casualty evacuation. We present a comparison of three methods to solve this problem: namely we implement a Deep Q-Learning model, an ε-greedy tabular Q-Learning model, and an online optimization framework. Our computational experiments, designed using simple grid-world environments with random adversaries showcase how these approaches work and compare them in terms of performance, accuracy, and computational time.R.Y. is partially supported by NSF DMS 1916037 and Consortium for Robotics and Unmanned Systems Education and Research (CRUSER).NSF DMS 1916037Consortium for Robotics and Unmanned Systems Education and Research (CRUSER