with the need for pro eliminated under obligatory control, hornstein argues that it follows naturally that pro should be altogether eliminated from the theory as it is equivalent to little pro. in particular, little pro is equivalent to an indefinite or a definite pronoun (similar to english one) and has the same distribution as non-obligatory control pro. with non-obligatory control, an overt embedded subject may be introduced (25) or omitted (26), and omitting the embedded subject may result in an arbitrary reading. additionally, the overt subject may not be moved out of the embedded clause, (27).