Soft Concurrent Constraint Programming

Soft constraints extend classical constraints to represent multiple consistency levels, and thus provide a way to express preferences, fuzziness, and uncertainty. While there are many soft constraint solving formalisms, even distributed ones, by now there seems to be no concurrent programming framework where soft constraints can be handled. In this paper we show how the classical concurrent constraint (cc) programming framework can work with soft constraints, and we also propose an extension of cc languages which can use soft constraints to prune and direct the search for a solution. We believe that this new programming paradigm, called soft cc (scc), can be also very useful in many web-related scenarios. In fact, the language level allows web agents to express their interaction and negotiation protocols, and also to post their requests in terms of preferences, and the underlying soft constraint solver can find an agreement among the agents even if their requests are incompatible.Comment: 25 pages, 4 figures, submitted to the ACM Transactions on Computational Logic (TOCL), zipped file

Size and soft budget constraints

There is much evidence against the so-called "too big to fail" hypothesis in the case of bailouts to sub-national governments. We look at a model where districts of different size provide local public goods with positive spillovers. Matching grants of a central government can induce socially-efficient provision, but districts can still exploit the intervening central government by inducing direct financing. We show that the ability of a district to induce a bailout from the central government and district size are negatively correlated

Decentralized Financing, Centralized Financing and the Dual Track System: Toward a New Theory of Soft Budget Constraints

I put forward a new theoretical framework to analyze the relationship between soft budget constraint syndrome and the economic performances of firms. It differs from the existing theoretical framework, à la Dewatripont and Maskin (1995), in the soft budget constraint literature. In this paper, soft budget constraint syndrome arises when firms that are expected to lose money are financed. The paper highlights a trade-off between hard and soft budget constraints. While soft budget constraints may compromise firms' incentives to improve performances, an all-out effort to harden budget constraints may put macro stability at risk, especially for economies suffering from allocative inefficiency. Based on this trade-off, the paper shows that a transition from centralized financing to decentralized financing in fact compromises firms' incentives to improve their performances, whereas a transition from centralized financing to a dual track system enhances efficiency. In the dual track system, budget constraints are soft in the centralized track but the macro stability of the economy is assured as a result. The macro stability enhances the disciplinary effect of hard budget constraints in the decentralized track, which in turn promotes firms' incentives to improve performances. The paper sheds light on a complementary relation between soft budget constraint syndrome in the state sector (i.e., the centralized track) and the remarkable growth of the non-state sector (i.e., the decentralized track) in China.http://deepblue.lib.umich.edu/bitstream/2027.42/39646/3/wp261.pd

A constraint-based approach to noun phrase coreference resolution in German newspaper text

In this paper, we investigate the usefulness of a wide range of features for their usefulness in the resolution of nominal coreference, both as hard constraints (i.e. completely removing elements from the list of possible candidates) as well as soft constraints (where a cumulation of violations of soft constraints will make it less likely that a candidate is chosen as the antecedent). We present a state of the art system based on such constraints and weights estimated with a maximum entropy model, using lexical information to resolve cases of coreferent bridging

Forbearance lending and soft budget constraints in a model of multiple heterogeneous bank financing

Empirical evidence suggests that banks often engage in refinancing of intrinsically insolvent debtors instead of writing of their non-performing loans. Such forbearance lending may induce soft budget constraints for the debtors, as it diminishes their incentives to thwart default. This paper introduces a model of coordination failure to analyze how a relationship bank affects the incidence of forbearance lending and soft budget constraints by signaling its credit decision to other creditors. We find that the relationship bank's signaling ability enhances its incentives to engage in forbearance lending and infuences the conditions under which debtors face soft budget constraints. --coordination failure,global games,asymmetric information,forbearance lending,soft budget constraints

Budget constraints in party-states nested in power relations: the key to different paths of transformation

This paper revisits the widely known and used concept of soft budget constraints in party-states introduced by Kornai (1980), from the point of view of a comparative analytical model (Csanádi, 2003). It embeds budget constraints in the structure of power relations described by the model as the interactive structure of interrelations between party-, state- and economic decision-makers on the level of individual actors. In this respect, we argue, that soft budget constraints will acquire several new structure-specific traits presented in the paper that are worth to consider. The new properties of budget constraints nested in power relations will define the selectively soft and hard constraints of self-reproduction of the net. The distribution of power will define the dynamics of reproduction of the structure as a whole. The differences in the distribution of power will be responsible for the frequency of its hardening reproduction constraints. Soft and hard reproduction constraints and its dynamics in different power distributions will contribute to several theoretical conclusions concerning the selfsimilarities and structural differences in the operation and different paths of disintegration, collapse and transformations of party-states.communism, socialism, party-state system, comparative model, soft budget constraint, selectivity, reproduction constraints, disintegration, collapse, transformation

Exploring soft constraints on effective actions

We study effective actions for simultaneous breaking of space-time and internal symmetries. Novel features arise due to the mixing of Goldstone modes under the broken symmetries which, in contrast to the usual Adler's zero, leads to non-vanishing soft limits. Such scenarios are common for spontaneously broken SCFT's. We explicitly test these soft theorems for $\mathcal{N}=4$ sYM in the Coulomb branch both perturbatively and non-perturbatively. We explore the soft constraints systematically utilizing recursion relations. In the pure dilaton sector of a general CFT, we show that all amplitudes up to order $s^{n} \sim \partial^{2n}$ are completely determined in terms of the $k$-point amplitudes at order $s^k$ with $k \leq n$. Terms with at most one derivative acting on each dilaton insertion are completely fixed and coincide with those appearing in the conformal DBI, i.e. DBI in AdS. With maximal supersymmetry, the effective actions are further constrained, leading to new non-renormalization theorems. In particular, the effective action is fixed up to eight derivatives in terms of just one unknown four-point coefficient and one more coefficient for ten-derivative terms. Finally, we also study the interplay between scale and conformal invariance in this context.Comment: 20+4 pages, 1 figure; v2: references added, typos corrected; v3: typos corrected, JHEP versio