On the Word Problem for ÓÐ-Categories, and the Properties of Two-Way Communication
Source: University of Calgary
The word problem for categories with free products and co-products (sums), ÓÐ-categories, is directly related to the problem of determining the equivalence of certain processes. Indeed, the maps in these categories may be directly interpreted as processes which communicate by two-way channels. The maps of an ÓÐ -category may also be viewed as a proof theory for a simple logic with a game theoretic interpretation. The cut-elimination procedure for this logic determines equality only up to certain permuting conversions. As the equality classes under these permuting conversions are finite, it is easy to see that equality between cut-free terms (even in the presence of the additive units) is decidable. Unfortunately, this does not yield a tractable decision algorithm as these equivalence classes can contain exponentially many terms.