Metamath Proof Explorer


Theorem gneispacern

Description: A generic neighborhood space has a range that is a subset of the powerset of the powerset of its domain. (Contributed by RP, 15-Apr-2021)

Ref Expression
Hypothesis gneispace.a
|- A = { f | ( f : dom f --> ( ~P ( ~P dom f \ { (/) } ) \ { (/) } ) /\ A. p e. dom f A. n e. ( f ` p ) ( p e. n /\ A. s e. ~P dom f ( n C_ s -> s e. ( f ` p ) ) ) ) }
Assertion gneispacern
|- ( F e. A -> ran F C_ ( ~P ( ~P dom F \ { (/) } ) \ { (/) } ) )

Proof

Step Hyp Ref Expression
1 gneispace.a
 |-  A = { f | ( f : dom f --> ( ~P ( ~P dom f \ { (/) } ) \ { (/) } ) /\ A. p e. dom f A. n e. ( f ` p ) ( p e. n /\ A. s e. ~P dom f ( n C_ s -> s e. ( f ` p ) ) ) ) }
2 1 gneispacef
 |-  ( F e. A -> F : dom F --> ( ~P ( ~P dom F \ { (/) } ) \ { (/) } ) )
3 2 frnd
 |-  ( F e. A -> ran F C_ ( ~P ( ~P dom F \ { (/) } ) \ { (/) } ) )