This paper chronicles some issues that arose in attempting to implement two simple planners that interleave planning and execution. (For brevity, such planners will be called IPE planners.) The IPE planners are based on UCPOP (Barrett et al. 1993), a classic operator-based planner using goal-regression. Unfortunately, while the planners succeeded on very simple problems, they failed on problems...

Domain-independent planning is a hard combinatorial problem. Taking into account plan quality makes the task even more difficult. This article introduces Planning by Rewriting (PbR), a new paradigm for efficient high-quality domain-independent planning. PbR exploits declarative plan-rewriting rules and efficient local search techniques to transform an easy-to-generate, but possibly suboptimal, ...

Planning by Rewriting (PbR) is a paradigm for efficient high-quality planning that exploits declarative plan rewriting rules and efficient local search techniques to transform an easy-to-generate, but possibly suboptimal, initial plan into a high-quality plan. In addition to addressing planning efficiency and plan quality, PbR offers a new anytime planning algorithm. The plan rewriting rules ca...

Telecommunications is increasingly vital to the society at large, and has become essential to business, academic, as well as social activities. Due to the necessity to have access to telecommunications, the deployment requires regulations and policy. Otherwise, the deployment of the infrastructures would contribute to environment, and human complexities rather than ease of use. However, the for...

Watkins has conjectured that if R is the rank of the group of rational points of an elliptic curve E over the rationals, then 2 divides the modular parametrisation degree. We show, for a certain class of E, chosen to make things as easy as possible, that this divisibility would follow from the statement that a certain 2adic deformation ring is isomorphic to a certain Hecke ring, and is a comple...

The debts’ clearing problem is about clearing all the debts in a group of n entities (eg. persons, companies) using a minimal number of money transaction operations. In a previous paper we conjectured the problem to be NP-complete. In this paper we prove that it is NP-hard in the strong sense and also NP-easy. We also show the same results for a restricted version of the problem.

To facilitate the implementation of workflows, enterprise and workflow system vendors typically provide sets of workflow templates for their software. Each of these templates depicts a variant of how a particular business process can be supported by the software. The user of such a system can save the effort of creating the models and the links to system components from scratch by selecting and...

Nondeterminacy implies two unpleasant properties for testing and debugging parallel programs: successive executions of the same program with the same input values often do not show identical behaviour and watching the program influences the execution. It is therefore not always possible to test and debug parallel programs like sequential ones. This article presents an approach how to make test,...

I present a probabilistic analysis of propositional STRIPS planning. The analysis considers two assumptions. One is that each possible precondition (likewise postcondition) of an operator is selected independently of other pre-and postconditions. The other is that each operator has a xed number of preconditions (likewise postconditions). Under both assumptions , I derive bounds for when it is h...