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

Lemma trivIsetU1 A P :
{in P, forall B, [disjoint A & B]} -> trivIset P -> set0 \notin P ->
trivIset (A |: P) /\ A \notin P.