Parallelism in Inheritance Hierarchies with Exceptions

In a recent paper, Etherington & Reiter formalized a simple version of semantic networks with exceptions in terms of Reiter's Default Logic. With this approach they were able to formally characterize the correctness of an inference algorithm in terms of Default Logic, and exhibited an algorithm that was correct in this sense. Finally, they concluded that massively parallel architectures for semantic networks, such as NETL apparently cannot implement this algorithm. In this paper, we present a different massively parallel architecture for the simplified semantic networks outlined in their paper which appears to avoid the objections to NETL. We also present some results of simulations in this framework of the examples presented in Etherington and Reiter.