intuition.
eapply leRat_trans.
eapply eqRat_impl_leRat.
eapply (sumList_filter_partition (fun a => if (in_dec (EqDec_dec _) a (getSupport c)) then true else false)).
eapply leRat_trans.
2:{
eapply eqRat_impl_leRat.
symmetry.
eapply ratAdd_0_r.
}
eapply ratAdd_leRat_compat.
eapply leRat_trans.
eapply sumList_subset_le.
intuition.
eapply filter_NoDup.
trivial.
eapply (getSupport_NoDup c).
intuition.
eapply filter_In in H0.
intuition.
destruct (in_dec (EqDec_dec eqd) a (getSupport c)); intuition.
discriminate.
eapply evalDist_sum_le_1.
eapply eqRat_impl_leRat.
eapply sumList_0.
intuition.
eapply filter_In in H0.
intuition.
destruct (in_dec (EqDec_dec eqd) a (getSupport c)).
simpl in *.
discriminate.
eapply getSupport_not_In_evalDist.
trivial.
Qed.

Theorem evalDist_1_0 :
forall (A : Set){eqd : EqDec A}(c : Comp A) a,
well_formed_comp c ->
evalDist c a == 1 ->
(forall b, b <> a -> evalDist c b == 0).