Equivalence Problems for Regular sets of Word Morphisms

Despite its firm basis in theoretical biology L systems theory has had some far reaching repercussions in mathematics and theoretical computer science. One of these is the emphasis on iterated composition of morphisms on a free monoid (word morphisms). This leads naturally to set equivalence problems, familiar from formal language theory, and sequence equivalence problems (variously known also as strong equivalence, graph equivalence or tree equivalence problems in deterministic L systems theory).