Relative observability in coordination control

Relative observability was introduced and studied in the framework of partially observed discrete-event systems as a condition stronger than observability and weaker than normality. Unlike observability, relative observability is closed under language unions, which makes it interesting for practical applications. In this paper, we investigate this notion in the framework of coordination control. We prove that conditional normality is stronger than conditional relative observability, hence it can be used in coordination control instead of conditional normality. We present a distributive procedure to compute a conditionally controllable and conditionally observable sublanguage of the specification that contains the supremal conditionally relative observable sublanguage.