Vote buying revisited: implications for receipt-freeness

In this paper, we analyse the concept of vote buying based on examples that try to stretch the meaning of the concept. Which ex- amples can still be called vote buying, and which cannot? We propose several dimensions that are relevant to qualifying an action as vote buy- ing or not. As a means of protection against vote buying and coercion, the concept of receipt-freeness has been proposed. We argue that, in or- der to protect against a larger set of vote buying activities, the concept of receipt-freeness should be interpreted probabilistically. We propose a general definition of probabilistic receipt-freeness by adapting existing definitions of probabilistic anonymity to voting

Distributed Detection of Cycles

Distributed property testing in networks has been introduced by Brakerski and Patt-Shamir (2011), with the objective of detecting the presence of large dense sub-networks in a distributed manner. Recently, Censor-Hillel et al. (2016) have shown how to detect 3-cycles in a constant number of rounds by a distributed algorithm. In a follow up work, Fraigniaud et al. (2016) have shown how to detect 4-cycles in a constant number of rounds as well. However, the techniques in these latter works were shown not to generalize to larger cycles $C_k$ with $k\geq 5$. In this paper, we completely settle the problem of cycle detection, by establishing the following result. For every $k\geq 3$, there exists a distributed property testing algorithm for $C_k$-freeness, performing in a constant number of rounds. All these results hold in the classical CONGEST model for distributed network computing. Our algorithm is 1-sided error. Its round-complexity is $O(1/\epsilon)$ where $\epsilon\in(0,1)$ is the property testing parameter measuring the gap between legal and illegal instances

Three Optimisations for Sharing

In order to improve precision and efficiency sharing analysis should track both freeness and linearity. The abstract unification algorithms for these combined domains are suboptimal, hence there is scope for improving precision. This paper proposes three optimisations for tracing sharing in combination with freeness and linearity. A novel connection between equations and sharing abstractions is used to establish correctness of these optimisations even in the presence of rational trees. A method for pruning intermediate sharing abstractions to improve efficiency is also proposed. The optimisations are lightweight and therefore some, if not all, of these optimisations will be of interest to the implementor.Comment: To appear in Theiry and Practice of Logic Programmin

Survey of Distributed Decision

We survey the recent distributed computing literature on checking whether a given distributed system configuration satisfies a given boolean predicate, i.e., whether the configuration is legal or illegal w.r.t. that predicate. We consider classical distributed computing environments, including mostly synchronous fault-free network computing (LOCAL and CONGEST models), but also asynchronous crash-prone shared-memory computing (WAIT-FREE model), and mobile computing (FSYNC model)

Optimal agglomeration and regional policy

This paper studies the social desirability of agglomeration and the efficiency arguments for regional policy in a simple, analytically solvable ‘new economic geography’ model with two trade integrating regions. The location pattern emerging as market equilibrium is ?-shaped, featuring dispersion of firms both at high and low trade costs and stable equilibria with partial agglomeration of firms in addition to core periphery equilibria for intermediate levels of trade costs. Our central finding is that the market equilibrium is characterised by over-agglomeration for high trade costs and under-agglomeration for low trade costs. For an intermediate level of trade costs, the market equilibrium yields the socially optimal degree of agglomeration. An important implication of this result is that, on efficiency grounds, regional policy should foster the dispersion of firms for a range of high trade costs only, but agglomeration for a range of low trade costs. Hence, regional policies, such as those pursued by the European Union (which are aimed at fostering dispersion in general), is counterproductive when trade integration is deep enough JEL-Classification: F12, F15, F22, R12, R50 Keywords: economic geography, regional policy, optimal agglomeration, welfare