Metamath Proof Explorer


Theorem acsfn0

Description: Algebraicity of a point closure condition. (Contributed by Stefan O'Rear, 3-Apr-2015)

Ref Expression
Assertion acsfn0 ( ( 𝑋𝑉𝐾𝑋 ) → { 𝑎 ∈ 𝒫 𝑋𝐾𝑎 } ∈ ( ACS ‘ 𝑋 ) )

Proof

Step Hyp Ref Expression
1 0ss ∅ ⊆ 𝑎
2 1 a1bi ( 𝐾𝑎 ↔ ( ∅ ⊆ 𝑎𝐾𝑎 ) )
3 2 rabbii { 𝑎 ∈ 𝒫 𝑋𝐾𝑎 } = { 𝑎 ∈ 𝒫 𝑋 ∣ ( ∅ ⊆ 𝑎𝐾𝑎 ) }
4 0ss ∅ ⊆ 𝑋
5 0fin ∅ ∈ Fin
6 acsfn ( ( ( 𝑋𝑉𝐾𝑋 ) ∧ ( ∅ ⊆ 𝑋 ∧ ∅ ∈ Fin ) ) → { 𝑎 ∈ 𝒫 𝑋 ∣ ( ∅ ⊆ 𝑎𝐾𝑎 ) } ∈ ( ACS ‘ 𝑋 ) )
7 4 5 6 mpanr12 ( ( 𝑋𝑉𝐾𝑋 ) → { 𝑎 ∈ 𝒫 𝑋 ∣ ( ∅ ⊆ 𝑎𝐾𝑎 ) } ∈ ( ACS ‘ 𝑋 ) )
8 3 7 eqeltrid ( ( 𝑋𝑉𝐾𝑋 ) → { 𝑎 ∈ 𝒫 𝑋𝐾𝑎 } ∈ ( ACS ‘ 𝑋 ) )