On the word problem for SP-categories, and the properties of two-way communication

Luigi Santocanale J. Robin B. Cockett On the word problem for SP-categories, and the properties of two-way communication http://arxiv.org/abs/0904.1529 2009 CoRR abs/0904.1529 db/journals/corr/corr0904.html#abs-0904-1529 informal publication