Global Instance Finite_unit : Finite unit.
Global Hint Resolve transform_pair_bijection : core.

Lemma sumFQ_single_lst {X} (x0 : X) (xs : list X) (f : X -> Q) :
In x0 xs ->
NoDup xs ->
(forall x, x <> x0 -> f x == 0) ->
Qsum (map f xs) == f x0.