Link deletion in model elimination
In this paper we investigate a powerful subsumption concept which can be used to prune the search space in model elimination. The technique can be implemented easily by deleting links connecting the literals of input clauses. We study the cases in which link deletion strategies are complete and show that a large class of them is compatible with a slightly restricted form of regularity, which is the most popular refinement of model elimination. In this way, we combine two alternative and in general not necessarily compatible approaches to reduce the branching rate of the search in model elimination. One the one hand we have structural restrictions on the tableaux — on the other, with our subsumption concept, we exploit knowledge about the whole search tree. Both types of refinements have been integrated into a new proof system whose performance is demonstrated in a couple of experiments.
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