Blackboard relations in the mu Log coordination model

This paper describes coordination relations, that are relations that induce the presence or absence of data on some dataspaces from the presence or ab sence of other data oil other dataspaces. To that end we build upon previous work on the mu Log model and show that t he coordination relations carl be easily incorporated in it. This is achiev ed, on the one hand, by means of novel auxiliary operations, not classicall y used in Linda-like languages, and, on the other hand, by a translation te chnique reducing: the extended mu Log model to the core model augmented wit h the auxiliary operations. Among the most significant ones are multiple re ad and get operations on a blackboard, readall and getall operations, and t ests for the absence of data on blackboards. Although simple, the form of coordination relations we propose is quite pow erful as evidenced by a few examples including relations coming from the ob ject-oriented paradigm such as inheritance relations.