Triangulated Structures for projective Modules

We give a characterisation of those local not necessary commutative rings, for which the category of projective modules admits a triangulation with the identity as translation functor. By "admits a triangulation" we mean that the category can be given the structure of a triangulated category that satisfies the standard set of axioms including the octahedral axiom.Comment: 19 page

Chiral spin liquid in a two-dimensional two-component helical magnet

A low-temperature method is developed, suited for the two-dimensional two-component classical helical magnet. Four phases on the phase diagram as functions of temperature and helicity parameter of the Hamiltonian are found. Among the three ordered phases two show magnetic order: the usual algebraic correlations of the magnetization and the algebraic correlations of the magnetization in the frame rotating according with the helical order. A chiral spin liquid phase emerges directly from the paramagnetic phase and has a scalar parity-breaking pitch of the magnetization as the order parameter. The chiral phase transition is found to be of a continuous second order type with a modified by the long-range interaction Ising universality class. All the critical exponents are calculated in the second and the third order of an $\epsilon$-expansion. A new scaling relationship replacing the Josephson's one is found.Comment: v2: Fig.2 and Eqs. (45) and (46) as first submitted to PR

Institutionalization of Imported Rules in the European Union's New Member States: Bringing Politics Back in the Research Agenda

This paper sets out to explore the puzzle of possible institutionalization or reversal of rules 'imported' by new member states from Central and Eastern Europe during their preparation for accession to the EU. It argues that the institutionalization of formal rules adopted as part of enlargement requirements is not automatic post accession. New formal rules can be reversed, supported by secondary rules and institutionalized or ignored and not implemented. The paper proposes a politics framework that suggests that these different outcomes will be influenced by the environment of weak post communist states and will depend on the area specific configuration of formal and informal veto players and on the EU's ability to impose sanctions. In the case of non acquis imported rules, reversal of formal rules would be possible without sanctions whereas in the case of acquis rules, the likely outcomes are institutionalization or 'empty shells'. Another outcome, 'capture' of the new rules is likely in areas with distributive implications.enlargement; East-Central Europe; acquis communautaire; institutionalisation; administrative adaptation

Deposit Insurance During EU Accession

The paper presents a brief review of the systems of deposit insurance in accession countries, comparing their level of harmonization with the perspective of their EU integration. Studying the different practices of deposit insurance in the context of developing financial safety nets in future Europe we have found that: (i) there is overinsurance of deposits in accession countries, and (ii) that this could lead to increasing moral hazard, incentives deformation and increasing costs of banking intermediation in the whole euro area.http://deepblue.lib.umich.edu/bitstream/2027.42/40003/3/wp617.pd

Lossy Channel Games under Incomplete Information

In this paper we investigate lossy channel games under incomplete information, where two players operate on a finite set of unbounded FIFO channels and one player, representing a system component under consideration operates under incomplete information, while the other player, representing the component's environment is allowed to lose messages from the channels. We argue that these games are a suitable model for synthesis of communication protocols where processes communicate over unreliable channels. We show that in the case of finite message alphabets, games with safety and reachability winning conditions are decidable and finite-state observation-based strategies for the component can be effectively computed. Undecidability for (weak) parity objectives follows from the undecidability of (weak) parity perfect information games where only one player can lose messages.Comment: In Proceedings SR 2013, arXiv:1303.007

Dual Inflation Under the Currency Board: The Challenges of Bulgarian EU Accession

The importance of analysing inflation sources and dynamics in Bulgaria is imposed by (i) the long run process of price and inflation convergence to the Euro area and (ii) by the Currency Board operating in the country. In this study we make an attempt to estimate Balassa - Samuelson (BS) effect in Bulgaria (after the introduction of the Currency Board). The BS explanation of inflation (or dual inflation) has acquired both academic recognition and popularity in practice in the recent years. The results of our empirical estimation do not provide a robust verification of the existence of BS effect in spite of the observed prerequisites and the accompanying economic indicators interrelations. Actually there are several factors that interfere with the BS effect lying in the wage convergence process in both sectors and others that influence productivity developments in the sectors. This prompts that the price movement in the country has other driving motions – above all wage setting and incomplete price liberalization, other factors productivity, imported inflation (pass trough) and inflation generated by the temporary gaps between money demand and money supply.http://deepblue.lib.umich.edu/bitstream/2027.42/39872/3/wp487.pd