Partial order reduction (POR) and net unfoldings are two alternative methods to tackle statespace explosion caused by concurrency. In this paper, we propose the combination of both approaches in an effort to combine their strengths. We first define, for an abstract execution model, unfolding semantics parameterized over an arbitrary independence relation. Based on it, our main contribution is a...

We study an alternative model of infinitary term rewriting. Instead of a metric on terms, a partial order on partial terms is employed to formalise convergence of reductions. We consider both a weak and a strong notion of convergence and show that the metric model of convergence coincides with the partial order model restricted to total terms. Hence, partial order convergence constitutes a cons...

This paper considers the problem of transforming a resource feasible, fixed-times schedule into a partial order schedule (POS) to enhance its robustness and stability properties. Whereas a fixed-times schedule is brittle in the face of unpredictable execution dynamics and can quickly become invalidated, a POS retains temporal flexibility whenever problem constraints allow it and can often absor...

Graph-based learning methods explicitly consider the relations between two entities (i.e., vertices) for learning the prediction function. They have been widely used in semi-supervised learning, manifold ranking, and clustering, among other tasks. Enhancing the expressiveness of simple graphs, hypergraphs formulate an edge as a link to multiple vertices, so as to model the higher-order relation...

The stable semantics has become a prime candidate for knowledge representation and reasoning. The rules associated with propositional logic programs and the stable semantics are not expressive enough to let one write concise optimization programs. We propose an extension to the language of logic programs that allows one to express optimization problems in a suitable well. In earlier work we def...

Partial Order Reduction (POR) techniques improve the basic model checking algorithm by reducing the numbers of states and transitions explored in verifying a property of the model. In the “ample set” POR framework for the verification of an LTL −X formula φ, one associates to each state s a subset Ts of the set of all transitions enabled at s. The approach requires that whenever Ts is a proper ...

We present two concurrent semantics (i.e. semantics where concurrency is ex-plicitely represented) for CC programs with atomic tells. One is based on simple partial orders of computation steps, while the other one is based on contextual nets and it is an extension of a previous one for eventual CC programs. Both such semantics allow us to derive concurrency, dependency, and nondeterminism infor...

Systematic testing, first demonstrated in small, specialized cases 15 years ago, has matured sufficiently for large-scale systems developers to begin to put it into practice. With actual deployment come new, pragmatic challenges to the usefulness of the techniques. In this paper we are concerned with scaling dynamic partial order reduction, a key technique for mitigating the state space explosi...

Model checking of asynchronous systems is traditionally based on the interleaving model, where an execution is modeled by a total order between events. Recently, the use of partial order semantics that allows independent events of concurrent processes to be unordered is becoming popular. Temporal logics that are interpreted over partial orders allow specifications relating global snapshots, and...

If T⃗ denotes a vector tangent to C at t,x,u then the direction numbers of T⃗ must be a,b, f. But then (1.2) implies that T⃗ n⃗, which is to say, T⃗ lies in the tangent plane to the surface S. But if T⃗ lies in the tangent plane, then C must lie in S. Evidently, solution curves of (1.2) lie in the solution surface S associated with (1.2). Such curves are called characteristic curves for (1.2). W...