Characterizing termination in LOTOS via testing

We study termination of LOTOS behaviors. In order to characterize termination, we rst deene a testing semantics for LOTOS in the classical way giving a fully abstract characterization in terms of acceptance sets. We show that this testing semantics does not properly capture termination. Then we modify the testing semantics by extending the class of admissible tests, to obtain a new equivalence that is a congruence with respect to the enabling operator. Then, we study alternative deenitions of testing in order to capture termination, and we relate them each other, getting a Hierarchy of termination, which besides proves that the rst termination semantics is in fact the most adequate one.