The problem considered is to construct all solutions of an equation for a tuple of languages. The tuple in synchronous composition should equal a considered language. Of special interest are the maximal solutions with respect to a partial order relation on the set of solutions. The motivation of the problem is coordination control. The approach to the problem is to transform the equation to a fixedpoint equation. An algorithm is proposed which constructs tuples of maximal solutions by convergence of a sequence of tuples to a solution of the fixed-point equation. Modular supervisory control is shown to benefit from the proposed approach.@en