Section BigSetOps.
Variables T I : finType.
Implicit Types (U : {pred T}) (P : pred I) (A B : {set I}) (F :  I -> {set T}).

Lemma setC_bigcup J r (P : pred J) (F : J -> {set T}) :
~: (\bigcup_(j <- r | P j) F j) = \bigcap_(j <- r | P j) ~: F j.