  Commutativity has the same inherent limitations as compatibility. Then, it is
worth conceiving simple concurrency control techniques. We propose a restricted
form of commutativity which increases parallelism without incurring a higher
overhead than compatibility. Advantages of our proposition are: (1)
commutativity of operations is determined at compile-time, (2) run-time
checking is as efficient as for compatibility, (3) neither commutativity
relations, (4) nor inverse operations, need to be specified, and (5) log space
utilization is reduced.
