  A monster is an automaton in which every function from states to states is
represented by at least one letter. A modifier is a set of functions allowing
one to transform a set of automata into one automaton. We revisit some language
transformation algorithms in terms of modifier and monster. These new
theoretical concepts allow one to find easily some state complexities. We
illustrate this by retrieving the state complexity of the Star of Intersection
and the one of the Square root operation.
