induction 1; intros; subst.
inversion H0.
inversion H2; clear H2; subst.
eapply IHevalDet_steps;
trivial.
Qed.

Theorem evalDet_steps_done_eof_func : forall (A : Set) x (a : A) s,
evalDet_steps x (cs_done a s) ->
evalDet_steps x (@cs_eof A) ->
False.