delet associ sub vertic enforc follow formed rule formed rule composit state composit substat concurr composit state broken delet substat delet remain substat convert composit state non concurr param elem uml element delet delet composit state object elem elem composit state illeg argument except composit state composit state composit state elem state vertex vertex composit state subvertex model impl uml factori delet vertex composit state contain composit state composit state contain formed rule composit state composit substat concurr composit state broken delet substat delet remain substat contain composit state contain composit state concurr collect state vertex sibl contain composit state subvertex substat remain sibl size substat remain state vertex sibl sibl sibl composit state model impl uml factori delet sibl 