intuition.
simpl.
unfold indicator.
case_eq (P a); intuition.
rewrite ratMult_1_l.
eapply ratMult_0.
right.
eapply getSupport_not_In_evalDist.
intuition.
eapply H;
eauto.
rewrite ratMult_0_l.
eapply ratMult_0_l.
Qed.

Theorem evalDist_event_equiv :
forall (A : Set){eqd : EqDec A}(c : Comp A) a,
evalDist c a == Pr[x <-$ c; ret (eqb a x)].