End Plain.
Section Abelian.
Variable op : Monoid.com_law 1.
Local Notation "'*%M'" := op (at level 0).
Local Notation "x * y" := (op x y).

Lemma big_uniq (I : finType) (r : seq I) F :
uniq r -> \big[*%M/1]_(i <- r) F i = \big[*%M/1]_(i in r) F i.