Chain varieties of monoids

A variety of universal algebras is called a chain variety if its subvariety lattice is a chain. Non-group chain varieties of semigroups were completely classified by Sukhanov in 1982. Here we completely determine non-group chain varieties of monoids as algebras of tyoe (2,0).Comment: 76 pages, 3 figures, 3 tables. In comparison with the previous version, we made a number of linguistic corrections onl

The lattice of varieties of monoids

We survey results devoted to the lattice of varieties of monoids. Along with known results, some unpublished results are given with proofs. A number of open questions and problems are also formulated

Patterns of the block approach for structure analysis of chemical elements and issues in materials science

The authors developed a notion of the three-dimensional matrix of chemical elements, which made it possible to eliminate the main disadvantages of tabular forms of the structure of chemical elements developed by D.I. Mendeleev and the international community of IUPAC chemists. The three-dimensional structure is represented as an expanding conic matrix. At the same time, all known chemical elements up to number 118 are combined into four blocks. The block-structure made it possible to substantiate an electron-level formula, even for the proposed new chemical elements of the 5th block E with numbers 119 through 218. This allows for the development of a digital model for calculating interactions of chemical elements and obtaining new types of compounds and materials

Forecasting stock market returns over multiple time horizons

In this paper we seek to demonstrate the predictability of stock market returns and explain the nature of this return predictability. To this end, we introduce investors with different investment horizons into the news-driven, analytic, agent-based market model developed in Gusev et al. (2015). This heterogeneous framework enables us to capture dynamics at multiple timescales, expanding the model's applications and improving precision. We study the heterogeneous model theoretically and empirically to highlight essential mechanisms underlying certain market behaviors, such as transitions between bull- and bear markets and the self-similar behavior of price changes. Most importantly, we apply this model to show that the stock market is nearly efficient on intraday timescales, adjusting quickly to incoming news, but becomes inefficient on longer timescales, where news may have a long-lasting nonlinear impact on dynamics, attributable to a feedback mechanism acting over these horizons. Then, using the model, we design algorithmic strategies that utilize news flow, quantified and measured, as the only input to trade on market return forecasts over multiple horizons, from days to months. The backtested results suggest that the return is predictable to the extent that successful trading strategies can be constructed to harness this predictability.Comment: This is the version accepted for publication in a journal Quantitative Finance. A draft was posted here on 18 August 2015. 50 page

Predictable markets? A news-driven model of the stock market

We attempt to explain stock market dynamics in terms of the interaction among three variables: market price, investor opinion and information flow. We propose a framework for such interaction and apply it to build a model of stock market dynamics which we study both empirically and theoretically. We demonstrate that this model replicates observed market behavior on all relevant timescales (from days to years) reasonably well. Using the model, we obtain and discuss a number of results that pose implications for current market theory and offer potential practical applications.Comment: This is the version accepted for publication in a new journal Algorithmic Finance (http://algorithmicfinance.org). A draft was posted here on 29 Apri

Compact Source of Electron Beam for Facility of Electron-Beam Welding with the Location of the Electron Gun and the Source of High Voltage in a Single Monoblock. Concept and Bench Tests of the Monoblok Prototype

Представлен прототип компактного источника электронного пучка для установок электронно-лучевой сварки с расположением электронной пушки и источника высоковольтного напряжения в едином моноблоке. Размещение электронной пушки, источника высоковольтного напряжения, электроники управления пучком и питания накала катода источника электронного пучка для электронно-лучевой сварки в едином корпусе-моноблоке снижает вес и стоимость (за счёт уменьшения количества используемых материалов), объём и занимаемые производственные площади. Это существенно расширяет возможности применения представляемого типа источников электронного пучка в разнообразных областях деятельности человека, в том числе в космических технологиях в открытом пространстве космоса. Цель работы – показать целесообразность концепции компоновки источника электронного пучка в едином корпусе-моноблоке на примере стендовых испытаний прототипа источника-моноблока. Спроектирован и изготовлен прототип источника-моноблока. Проведены его предварительные стендовые испытания с лазерным подогревом катода. Обсуждаются возможные применения. Получен электронный ток источника до 70 мА с энергией 90 кэВ. Данный результат демонстрирует возможность практической реализации нового способа компоновки источника электронного пучкаA prototype of an electron beam compact source for electron-beam welding is presented. The electron gun and a high-voltage source are united in a single monoblock. The placement of the electron gun, the high-voltage source, the beam control electronics and the power supply of the cathode heating of the electron beam source for electron beam welding in a single monoblock housing reduces weight and cost by reducing the amount of materials used, volume and occupied production areas. This significantly expands the possibilities of using the presented type of electron beam sources in various fields of human activity, including space technologies in the open space of space. The purpose of the work is to show the expediency of the concept of arranging the electron beam source in the single monoblock housing as the example of bench tests of the source prototype. The prototype of the monoblock was designed and manufactured. Its preliminary bench tests with laser cathode heating were carried out. Its possible applications are discussed. An electron source current up to 70 mA with an energy of 90 keV was obtained. The result obtained demonstrates the possibility of practical implementation of a new method of arranging an electron beam sourc