Total order

Weak pseudo BL-algebras (WPBL-algebras) are non-commutative fuzzy structures which arise from pseudot-norms (i.e. the non-commutative versions of triangular norms). In this paper, we study the pairs of weak negations on WPBL-algebras, extending the case of weak negations on Esteva-Godo MTL-algebras. A geometrical characterization of the pairs of weak negations in bounded chains is provided.

Ring interconnects may be an attractive solution for future chip multiprocessors because they can enable faster links than buses and simpler switches than arbitrary switched interconnects. Moreover, a ring naturally orders requests sufficiently to enable directory-less coherence, but not in the total order that buses provide for snooping coherence. Existing cache coherence protocols for rings either establish a (total) ordering point (ORDERING-POINT) or use a greedy order (GREEDY-ORDER) with unbounded retries.

Given a collection of Boolean spatio-temporal(ST) event types, the cascading spatio-temporal pattern (CSTP) discovery process finds partially ordered subsets of event-types whose instances are located together and occur in stages. For example, analysis of crime datasets may reveal frequent occurrence of misdemeanors and drunk driving after bar closings on weekends and after large gatherings such as football games. Discovering CSTPs from ST datasets is important for application domains such as public safety (e.g. crime attractors and generators) and natural disaster planning(e.g. hurricanes). However, CSTP discovery is challenging for several reasons, including both the lack of computationally efficient, statistically meaningful metrics to quantify interestingness, and the large cardinality of candidate pattern sets that are exponential in the number of event types. Existing literature for ST data mining focuses on mining totally ordered sequences or unordered subsets. In contrast, this paper models CSTPs as partially ordered subsets of Boolean ST event types. We propose a new CSTP interest measure (the Cascade Participation Index) that is computationally cheap(O(n 2 ) vs. exponential, where n is the dataset size) as well as statistically meaningful. We propose a novel algorithm exploiting the ST nature of datasets and evaluate filtering strategies to quickly prune uninteresting candidates. We present a case study to find CSTPs from real crime reports and provide a statistical explanation. Experimental results indicate that the proposed multiresolution spatiotemporal(MST) filtering strategy leads to significant savings in computational costs.

In this paper, we present a performance comparison of database replication techniques based on total order broadcast. While the performance of total order broadcast-based replication techniques has been studied in previous papers, this paper presents many new contributions. First, it compares with each other techniques that were presented and evaluated separately, usually by comparing them to a classical replication scheme like distributed locking. Second, the evaluation is done using a finer network model than previous studies. Third, the paper compares techniques that offer the same consistency criterion (one-copy serializability) in the same environment using the same settings. The paper shows that, while networking performance has little influence in a LAN setting, the cost of synchronizing replicas is quite high. Because of this, total order broadcast-based techniques are very promising as they minimize synchronization between replicas.

A cop&g&z! order of the vertices of a directed acyclic graph G = (y E) is any total order ord such that if (x, y) f E, then x precedes y in ord. In this paper we consider the dynamic version of this problem, and provide simple algorithms and data structures achieving O(n) amortized time per edge insertion starting from an empty graph, which favorably compares to the trivial 0( m + n) time bound per operation obtained applying the off-line algorithm. The additional space requirement, beside the representation of the graph itself, is O(n). Experimental results show that our algorithm performs in practice orders of magnitude faster than the off-line algorithm.

... group communication, fault-tolerance, agreement problems, message passing, total ordering, global ordering, atomic multicast, atomic broadcast, classification, taxonomy ... Part of this research was conducted for the program “Fostering Talent in Emergent Research Fields ...

We begin by constructing the algebra of classical intervals and prove that it is a nondistributive abelian semiring. Next, we formalize the notion of interval dependency, along with discussing the algebras of two alternate theories of intervals: modal intervals, and constraint intervals. With a view to treating some problems of the present interval theories, we present an alternate theory of intervals, namely the "theory of optimizational intervals", and prove that it constitutes a rich S-field algebra, which extends the ordinary field of the reals, then we construct an optimizational complex interval algebra. Furthermore, we define an order on the set of interval numbers, then we present the proofs that it is a total order, compatible with the interval operations, dense, and weakly Archimedean. Finally, we prove that this order extends the usual order on the reals, Moore's partial order, and Kulisch's partial order on interval numbers.

Keywords. Classical interval arithmetic; Machine interval arithmetic; Interval dependency; Constraint intervals; Modal intervals; Classical complex intervals; Optimizational intervals; Optimizational complex intervals; S-field algebra; Ordering interval numbers.

Large databases with uncertain information are becoming more common in many applications including data integration, location tracking, and Web search. In these applications, ranking records with uncertain attributes needs to handle new problems that are fundamentally different from conventional ranking. Specifically, uncertainty in records' scores induces a partial order over records, as opposed to the total order that is assumed in the conventional ranking settings.

In this article we consider the Non-linear single varible Fuzzy-valued functions with regards to the total order relation defined on Fuzzy number space on the lines of [9]. Using this order relation and Hukuhara differentiability of fuzzy-valued functions we obtain the necessary and sufficient conditions for optimality of nonlinear single variable fuzzy-valued funcions.

The performance of a distributed system is affected by the various functions of its components. The interaction between components such as network nodes, computer systems and system programs is examined with special interest accorded to its effect on system reliability. At affordable time and space costs, the analytic hierarchy process (AHP) is used to determine how the reliability of a distributed system may be controlled by appropriately assigning weights to its components. Illustrative case studies, that display the system structure, the assignment of weights and the AHP handling are presented.

Causally and totally ordered communication support (CATOCS) has been proposed as important to provide as part of the basic building blocks for constructing reliable distributed systems. In this paper, we identify four major limitations to CATOCS, investigate the applicability of CATOCS to several classes of distributed applications in light of these limitations, and the potential impact of these facilities on communication scalability and robustness. From this investigation, we find limited merit and several potential problems in using CATOCS. The fundamental difficulty with the CATOCS is that it attempts to solve state problems at the communication level in violation of the

A general algebraic method for decoding all types of binary cyclic codes is presented. It is shown that such a method can correct t=[(d-1)/2] errors, where d is the true minimum distance of the given cyclic code. The key idea behind this decoding technique is a systematic application of the algorithmic procedures of Grobner bases to obtain the error-locator polynomial L(z). The discussion begins from a set of syndrome polynomials F and the ideal T(F) generated by F. It is proved here that the process of transforming F to the normalized reduced Grobner basis of I(F) with respect to the “purely lexicographical” ordering automatically converges to L(z). Furthermore, it is shown that L(z) can be derived from any normalized Grobner basis of I(F) with respect to any admissible total ordering. To illustrate this new approach, the procedures for decoding certain BCH codes and quadratic residue codes are demonstrated

We extend the concept of Arens regularity of a Banach algebra \(\mathcal{A}\) to the case that there is an \(\mathcal{O}\) -module structure on \(\mathcal{A}\) , and show that when S is an inverse semigroup with totally ordered subsemigroup E of idempotents, then A=ℓ 1(S) is module Arens regular if and only if an appropriate group homomorphic image of S is finite. When S is a discrete group, this is just Young’s theorem which asserts that ℓ 1(S) is Arens regular if and only if S is finite.

This paper focuses on the problem of the estimation of a distribution on an arbitrary complete separable metric space when the data points are subject to censoring by a general class of random sets. If the censoring mechanism is either totally observable or totally ordered, a reverse probability estimator may be defined in this very general framework. Functional central limit theorems are proven for the estimator when the underlying space is Euclidean. Applications are discussed, and the validity of bootstrap methods is established in each case.

Totally ordered multicast protocols have proved to be extremely useful in supporting fault-tolerant distributed applications. This paper compares the performance of the two main classes of protocols providing total order in large-scale systems: token-site and symmetric protocols. The paper shows that both classes of protocols can exhibit a latency close to 2D, where D is the message transit delay between two processes.

Let T n be the set of all trees of diameter 3 and n vertices. We show that the Laplacian energy of any tree in T n is strictly between the Laplacian energy of the path P n and the star S n , partially proving the conjecture that this holds for any tree. We also give a total order by the Laplacian energy in T n . Moreover, we show that this order depends only on the algebraic connectivity of the tree: the Laplacian energy increases as the algebraic connectivity decreases in T n .

Probability boxes are among the most simple and popular models used in imprecise probability theory, and many practical results concerning them exist in the literature. Nevertheless, little attention has been paid to their formal characterisation in the setting of Walley's behavioural theory of imprecise probabilities. This paper tries to remedy this situation by formalising, generalising and extending existing results as well as by giving new ones, within Walley's framework.

Purchase allocation is a multi criteria decision making (MCDM) problem. Multitude of qualitative and quantitative factors is involved in the multiple sourcing decisions. Analytic hierarchy process (AHP) has widely been used to find out the relative rankings of suppliers. AHP can be combined with regular supplier quantitative audit process. In classical AHP, decision maker (DM) has to pair wise compare suppliers for each factor, whereas the proposed audit based simplified AHP will remove the complexity of comparison. Quarterly audit-based AHP rankings and supplier performance probability products can be used in place of revenues in the backward recursive resource allocation knapsack model. This combined model will decompose purchase allocation problem into different stages and combine one supplier at each stage and provide the optimum and feasible solution in the end. Solution at each stage is also a feasible option. This model is only applicable when the total order quantity and the capacity of all suppliers are integer multiples of economic or minimum order quantity. This integrated model thus provides number of orders/supplier.

We investigate the ideal structure of the Toeplitz algebra $ \mathcal{T}(\Gamma) $ of a totally ordered abelian group $ \Gamma $ . We show that the primitive ideals of $ \mathcal{T}(\Gamma) $ are parametrised by the disjoint union $ X $ of the duals $ \hat{I} $ of the order ideals $ I $ of $ \Gamma $ , and identify the hull-kernel topology on $ X $ when the chain of orderideals in $ \Gamma $ is isomorphic to a subset of $ \{-\infty\}\cup \mathbb{Z} \cup \{\infty\} $

A proper vertex of a rooted tree with totally ordered vertices is a vertex that is less than all its proper descendants. We count several kinds of labeled rooted trees and forests by the number of proper vertices. Our results are all expressed in terms of the polynomials

Preference-based search (PBS) is a new search procedure for solving combinatorial optimization problems. Given a set of preferences between search decisions, PBS searches through a space of preferred solutions, which is tighter than the space of all solutions. The definition of preferred solutions is based on work in non-monotonic reasoning on priorities between defaults. The basic idea of PBS is quite simple: Always pick a locally best decision α. Either make the decision α or make other locally best decisions that allow to deduce ¬α and thus represent a counterargument for α. If there is no possible counterargument then PBS does not explore the subtree of ¬α. This pruning of the search space is obtained by nonmonotonic inference rules that are inspired by Doyle's TMS and that detect decisions belonging to all or no preferred solution. We show that PBS can optimally solve various important scheduling problems.

The (unit-cost) comparison tree model has long been the basis of evaluating the performance of algorithms for fundamental problems like sorting and searching. In this model, the assumption is that elements of some total order are not given to us directly, but only through a black-box, which performs comparisons between the elements and outputs the result of the comparison.

The poset sum construction is used to derive embedding theorems for several classes of generalized basic logic algebras (GBL-algebras). In particular it is shown that every n-potent GBL-algebra is embedded in a poset sum of finite n-potent MV-chains, and every normal GBL-algebra is embedded in a poset sum of totally ordered GMV-algebras. Representable normal GBL-algebras have poset sum embeddings where the poset is a forest. We also give a Conrad-Harvey-Holland-style embedding theorem for commutative GBL-algebras, where the poset summands are the real numbers extended with −∞. Finally, an explicit construction of a generic commutative GBL-algebra is given, and it is shown that every normal GBL-algebra embeds in the conucleus image of a GMV-algebra.

Several techniques for database replication using group communication have recently been proposed, namely, the Database State Machine, Postgres-R, and the NODO protocol. Although all rely on a totally ordered multicast for consistency, they differ substantially on how multicast is used. This results in different performance trade-offs which are hard to compare as each protocol is presented using a different load scenario and evaluation method. In this paper we evaluate the suitability of such protocols for replication of On-Line Transaction Processing (OLTP) applications in clusters of servers and over wide area networks. This is achieved by implementing them using a common infrastructure and by using a standard workload. The results allows us to select the best protocol regarding performance and scalability in a demanding but realistic usage scenario.

We connect different results about irreducible components of the Springer fibers of type A. Firstly, we show a relation between the Spaltenstein partition of the fibers and a total order ≺ on the set of standard Young tableaux. Next, using a result of Steinberg, we connect a work of the first author to the Robinson-Schensted map. We also perform the Spaltenstein study of the relative position of the Springer fibers and P 1 -fibrations of the flag manifold. This leads us to consider the adjacency relation on the set of standard Young tableaux and to define oriented and labeled graphs with the standard Young tableaux as vertices. Using this adjacency relation, we describe some smooth irreducible components of the Springer fibers. Finally, we show that these graphs can be identified with some full subgraphs of the Bruhat graph. . 14M15, 05E10.

We study a multi-item, multiple classes of demand, assemble-to-order system. The inventory of each item is kept at the item level and controlled by the base-stock policy with a finite capacity. Each item is replenished by an independent unreliable machine. Each type of demand arrives according to a Poisson process with an individual rate and requires a subset of the items. When the item requirements of an arriving demand cannot be satisfied entirely, two kinds of stockout may occur, namely total-orderservice and partial-order-service. We formulate the system as a queuing network and deduce that it is a quasi-birth-death process. Applying the matrix-geometric solution approach, we derive the exact joint steady-state distribution of on-order inventories, based on which we compute the order-based and item-based the fill rate within a time window and the service level. We present numerical examples to show how system performance varies with changes in system parameters to show the importance of taking machine failures into consideration.

In this paper, we utilize Cournot duopoly competition model to explore the insider trading issue, and focus our concern on changes in the financial side by introducing more owners as insiders, all of whom possess the same inside information and can trade in the stock market. We find that in reality, the output of listed firm decreases but quantity produced by other firm increases, though total output becomes less. Market makers are less responsive to both signals from real and financial sides, but will set stock prices higher with zero signals. The manager and each owner will order fewer stocks in the financial side, but the total order flow still depends upon the realized values of inside information. As the number of insiders increases, the profits of the manager and each owner will decrease correspondingly, so does the variance of the observed inside information. If the number approaches infinity, then all insiders' profits will also reach zero, and at the same time, there is no variance for the inside information. That is to say, all inside information is revealed to the public so the stock market is perfectly efficient.

Abstract\ Ve cOllf: iider multi-criteria f: iequent, ial decision making problems where the vcctor-" valucd evaluations arc compared by a given, fixed total ordering. Condit. ions for the opt. irnalit y of statiOIl<-l, r}'p () lich s;-weI the Bellman opti malit, y equation are given for a. special, but. important class of problems''v hell the eval uation of policies can be computed for the criteria, independently of each other. The anal)'sis requires special cafC as t. he t. opol ag, Y int. roduced by polnL\ visc convergence a. ncl the or< 1cr-topology ...

We consider the context of decision support for schedule modification after the computation off-line of a predictive optimal (or near optimal) schedule. The purpose of this work is to provide the decision-maker a characterization of possible modifications of the predictive schedule while preserving optimality. In the context of machine scheduling, the anticipated modifications are changes in the predictive order of operations on the machines. To achieve this goal, a flexible solution feasible w.r.t to operations deadlines, is provided instead of a single predictive schedule. A flexible solution represents a set of semi-active schedules and is characterized by a partial order on each machine, so that the total order can be set on-line, as required by the decision maker. A flexible solution is feasible if all the complete schedules that can be obtained by extension are also feasible.

We provide a pure algebraic version of the dynamical characterization of Conrad's property. This approach allows dealing with general group actions on totally ordered spaces. As an application, we give a new and somehow constructive proof of a theorem first established by Linnell: an orderable group having infinitely many orderings has uncountably many. This proof is achieved by extending to uncountable orderable groups a result about orderings which may be approximated by their conjugates. This last result is illustrated by an example of an exotic ordering on the free group given in the Appendix.

The special perturbation method considered in this paper combines simplicity of computer implementation, speed and precision, and can propagate the orbit of any material particle. The paper describes the evolution of some orbital elements based in Euler parameters, which are constants in the unperturbed problem, but which evolve in the time scale imposed by the perturbation. The variation of parameters technique is used to develop expressions for the derivatives of seven elements for the general case, which includes any type of perturbation. These basic differential equations are slightly modified by introducing one additional equation for the time, reaching a total order of eight. The method was developed in the Grupo de Dinámica de Tethers (GDT) of the UPM, as a tool for dynamic simulations of tethers. However, it can be used in any other field and with any kind of orbit and perturbation. It is free of singularities related to small inclination and/or eccentricity. The use of Euler parameters makes it robust. The perturbation forces are handled in a very simple way: the method requires their components in the orbital frame or in an inertial frame. A comparison with other schemes is performed in the paper to show the good performance of the method.

In this paper we present a model and solution methodology for production and inventory management problems that involve multiple resource constraints. The model formulation is quite general, allowing organizations to handle a variety of multi-item decisions such as determining order quantities, production batch sizes, number of production runs, or cycle times. Resource constraints become necessary to handle interaction among the multiple items. Common types of resource constraints include limits on raw materials, machine capacity, workforce capacity, inventory investment, storage space, or the total number of orders placed. For example, in a production environment, there may be limited workforce capacity and limits on machine capacities for manufacturing various product families. In a purchasing environment where a firm has multiple suppliers, there are often constraints for each supplier, such as the total order from each supplier cannot exceed the volume of the truck. We present efficient algorithms for solving both continuous and integer variable versions of the resource constrained production and inventory management model. The algorithms require the solution of a series of two types of subproblems: one is a nonlinear knapsack problem and the other is a nonlinear problem where the only constraints are lower and upper bounds on the variables. Computational testing of the algorithms is reported and indicates that they are effective for solving large-scale problems.

We view the incidence relation of a graph G=(I: E) as an order relation on ~ts vertices and edges, i.e. a <6 b if and only ifa is a vertex and b is an edge incident on a. This leads to the definition of the order-dimension of G as the minimum number of total orders on I'~ E whose intersection is <G. Our main result ~s the characterization of planar graphs as the graphs whose order-dimension does not exceed three. Strong versions of several known properties of planar graphs are ~mphed by this characterizahon These properhes include: each planar graph has arboricn) at most three and each planar graph has a plane embedding ~hose edges are straight line segments. A nice feature of this embedding ~s that the coordinates of the vertices have a purely combmatoriaI meaning.

The aim of minimal cost flow problem (MCFP) in fuzzy nature, which is denoted with FMCFP, is to find the least cost of the shipment of a commodity through a capacitated network in order to satisfy imprecise concepts in supply or demand of network nodes and capacity or cost of network links. Fuzzy supply-demand may arise in real problems, where incomplete statistical data or simulation results are used. Also, variation in the cost or capacity of links is commonly happening. In the present paper, after defining a total order on LR type fuzzy numbers, three models are studied; MCFP with fuzzy costs, MCFP with fuzzy supply-demand and a combination of two cases. For the first model, scaling negative cycle cancelling algorithm, which is a polynomial time algorithm, is proposed. For the second model, ''nominal flow'' is introduced which provides an efficient scheme for finding fuzzy flow. For the third model, we present an exact and some heuristic methods. Numerical examples are illustrated to demonstrate the efficiency of the proposed schemes. Finally, an application of this viewpoint in bus network planning problem is provided. MCFP using multi-level linear programming problem. But, they did not use the nice structure of network constraints. Moreover, their scheme was inefficient because the multi-level programming which was made applying their scheme, is non-convex and so it is NP-hard. On the other hand, a fuzzy programming problem may be interpreted as a multi-objective optimization . Keeping this point in mind, Noda et al. developed two network simplex methods for bi-objective MCFP and similarly Osman [9] found all efficient extreme integer solutions by non-polynomial time algorithms. Note that the comparison of solutions in combinatorial problems is often based on an additive cost function including a total order on solutions, e.g., Perny and Spanjaard [10] used a total preference binary relation on the solution space to develop some algorithms for preferred spanning trees and preferred paths problems. Also, Hashemi et al. generalized some combinatorial algorithms for MCFP with interval costs, using a total order. In continuation of their works, LR type fuzzy numbers are used in this paper and a total order on them is proposed by employing non-algebraic numbers . Furthermore, some combinatorial schemes for FMCFP are presented.

We consider the priority i n version problem in an actively replicated system. Priority i n version was originally de ned in the context of non-replicated systems. Therefore we rst introduce the concept of group priority inversion, which extends the concept of (local) priority inversion to the context of a group of processors that perform an actively replicated processing. We then present the properties of a request scheduling protocol to enforce a total ordering for the processing of requests while avoiding group priority i n versions. These properties have been implemented in a protocol that relies on a timed asynchronous system model equipped with a failure detector of the class 3S. The proposed solution allows to replicate a critical server while ensuring that the processing of all the incoming requests is consistent (mechanisms for solving the atomic broadcast problem) and predictable (mechanisms for solving the group priority inversion problem). Thus, the described request scheduling protocol is a key compo-

In this paper, we present a connectionist approach to preference learning. In particular, a neural network is trained to realize a comparison function, expressing the preference between two objects. Such a "comparator" can be subsequently integrated into a general ranking algorithm to provide a total ordering on some collection of objects. We evaluate the accuracy of the proposed approach using the LETOR benchmark, with promising preliminary results.

Unlike numerical preferences, preferences on attribute values do not show an inherent total order, but skyline computation has to rely on partial orderings explicitly stated by the user. In such orders many object values are incomparable, hence skylines sizes become unpractical. However, the Pareto semantics can be modified to benefit from indifferences: skyline result sizes can be essentially reduced by allowing the user to declare some incomparable values as equally desirable. A major problem of adding such equivalences is that they may result in intransitivity of the aggregated Pareto order and thus efficient query processing is hampered. In this paper we analyze how far the strict Pareto semantics can be relaxed while always retaining transitivity of the induced Pareto aggregation. Extensive practical tests show that skyline sizes can indeed be reduced about two orders of magnitude when using the maximum possible relaxation still guaranteeing the consistency with all user preferences.

Most practical work on AI planning systems during the last fifteen years has been based on hierarchical task network (HTN) d ecomposition, but until now, there has been very little analytical work on the properties of HTN planners. This paper describes how the complexity of HTN planning varies with various conditions on the task networks.

-based publish-subscribe system. The model is used to derive an efficient and scalable protocol for exactly-once delivery to large numbers (tens of thousands per broker) of content-based subscribers in either publisher order or uniform total order. Our protocol allows intermediate content filtering at each hop, but requires persistent storage only at the publishing site. It is tolerant of message drops, message reorderings, node failures, and link failures, and maintains only "soft" state at intermediate nodes. We evaluate the performance of our implementation both under failure-free conditions and with fault injection. 2. A protocol based on this knowledge model that tolerates broker crashes and dropped and re-ordered messages, that does not require hop-by-hop reliability of messages, and that requires stable storage only at the publishing broker and only soft-state [10] everywhere else.

The Realize system simplifies the development of complex applications by separating the application programming from the management of resources for soft real-time CORBA applications, and from the replication of CORBA objects to provide high availability and fault tolerance. Realize uses totally ordered multicast messages to maintain consistency of the states of the object replicas, and adjusts the degree of replication dynamically as resource availability changes. By measuring the usage of the resources and by monitoring the behavior of application objects, Realize allocates objects to processors and migrates objects between processors to balance the load on the processors. Realize employs a least-laxity scheduling strategy that meets soft real-time deadlines for tasks operating across multiple processors. Thus, with Realize, the difficult issues of distribution, real-time scheduling, load balancing, replication, consistency, and fault detection and recovery are hidden from the application programmer.

\Ve cOllf:iider multi-criteria f:iequent, ial decision making problems where the vcctor-"valucd evaluations arc compared by a given, fi xed total ordering. Condit.ions for the opt.irnalit�y of statiOIl<-l,r}' p()lich�s ;-weI the Bellman opti malit,y equation are given for a. special, but. important class of problems ' ' v hell the eval uation of policies can be computed for the criteria, independently of each other. The anal)'sis requires special cafC as t.he t.opol ag, Y int.roduced by polnL\visc convergence a. ncl the or<1cr-topology introduced by the prefer ence order arc in general incompatible. Re inforcement. learning algorithms are proposed and analY7,ed. Prelimina, ry computer experi ments confirm t, he val idit.y of the derived al gorithms. These type of multi-criteria prob lem� are most useful ,,,, hen t.here are several optimal solutions to a. problem and one 'Vl-lIlt.S to choose the one among these ,vhich is op timal according Lo another fixed criLerion. Possible application in robot.ics and repeat.ed ga. mes are outlined.

Given a finite set of vectors over a finite totally ordered domain, we study the problem of computing a constraint in conjunctive normal form such that the set of solutions for the produced constraint is identical to the original set. We develop an efficient polynomial-time algorithm for the general case, followed by specific polynomial-time algorithms producing Horn, dual Horn, and bijunctive constraints for sets of vectors closed under the operations of conjunction, disjunction, and median, respectively. We also consider the affine constraints, analyzing them by means of computer algebra. Our results generalize the work of Dechter and Pearl on relational data, as well as the papers by Hébrard and Zanuttini. They also complete the results of Hähnle et al. on multivalued logics and Jeavons et al. on the algebraic approach to constraints. We view our work as a step toward a complete complexity classification of constraint satisfaction problems over finite domains.

We present a new scalable fault-tolerant algorithm which ensures total order delivery of messages sent to multiple groups of processes. The algorithm is scalable in the sense that: (1) any process can multicast a message to one or more groups of processes without being forced to join those groups; (2) inter-group total order is ensured system-wide but, for each individual multicast, the number and size of messages exchanged depends only on the number of addressees; (3) failure detection does not need to be reliable.

We consider voting games induced by anonymous and top-unanimous social choice functions satisfying two additional conditions which we formulate and term "weak neutrality" and "effectivity regularity". The class of such social choice functions is quite broad, including every "t-refinement" of the Plurality Rule, Plurality with a Runoff, Approval Voting, the Majoritarian Compromise and the Single Transferable Vote, i.e., any selection from either of these social choice rules which is obtained via tie-breaking among candidates according to any total order t on the set of alternatives.

In this paper, we analyze the effect of Cournot competition with differentiated products on the real and financial decisions of a publiclyowned firm, with three different structures in the financial market: monopoly, duopoly and Stackelberg. We show that the degree of product differentiation does not affect the results found in the literature on insider trading, concerning the effect of the financial market structure on firms' outputs, the revelation of information and the insiders' orders. Besides, firms' output, the amount of information revealed in the stock price, the insiders' trading orders and the owners' profits are independent of the degree of product differentiation. The real market structure through the degree of product differentiation is found to determine the level of the compensation scheme earned by the manager, the market makers' response to the total order flow signal as well as the managers' profits. 1