We present a unified, axiomatic approach to proving lower bounds for the k-set agreement problem in both synchronous and asynchronous message-passing models. The proof involves constructing the set of reachable states, proving that these states are highly connected, and then appealing to a well-known topological result that high connectivity implies that set agreement is impossible. We construc...

Any model checker is limited by the time needed to determine the set of reachable states. We propose a hybrid model checker that successfully combines two approximation methods for fast and robust reachability analysis. Experiments on both sequential equivalence problems and safety property verification problems illustrate a speedup over previous SATbased unbounded verification methods.

This paper presents a novel reachability analysis technique which, while still maintaining a set of reached states, signiicantly reduces the size of this set through excluding a speciic subset of those states, referred to as pseudo-root states. Pseudo-root states are states which are not reachable from the unexplored state space of the nite model. Such states may be safely discarded from state ...

Time-varying graphs (T-graph) consist of a time-evolving set of graph snapshots (or graphlets). A T-graph property with potential applications in both computer and social network forensics is T-reachability, which identifies the nodes reachable from a source node using the T-graph edges over time period T. In this paper, we consider the problem of estimating the T-reachable set of a source node...

We approximate the backward reachable set of discrete-time autonomous polynomial systems using the recently developed occupation measure approach. We formulate the problem as an infinite-dimensional linear programming (LP) problem on measures and its dual on continuous functions. Then we approximate the LP by a hierarchy of finitedimensional semidefinite programming (SDP) programs on moments of...

In this paper we deal with the verification of safety properties of infinite-state systems modeled by term-rewriting systems. An over-approximation of the set of reachable terms of a termrewriting system R is obtained by automatically constructing a finite tree automaton. The construction is parameterized by a set E of equations on terms, and we also show that the approximating automata recogni...

We introduce a Markov chain model of concurrent quantum programs. This model is a quantum generalization of Hart, Sharir and Pnueli’s probabilistic concurrent programs. Some characterizations of the reachable space, uniformly repeatedly reachable space and termination of a concurrent quantum program are derived by the analysis of their mathematical structures. Based on these characterizations, ...