Metamath Proof Explorer


Theorem filfinnfr

Description: No filter containing a finite element is free. (Contributed by Jeff Hankins, 5-Dec-2009) (Revised by Stefan O'Rear, 2-Aug-2015)

Ref Expression
Assertion filfinnfr ⊢ F ∈ Fil ⁡ X ∧ S ∈ F ∧ S ∈ Fin → ⋂ F ≠ ∅

Proof

Step Hyp Ref Expression
1 filfbas ⊢ F ∈ Fil ⁡ X → F ∈ fBas ⁡ X
2 fbfinnfr ⊢ F ∈ fBas ⁡ X ∧ S ∈ F ∧ S ∈ Fin → ⋂ F ≠ ∅
3 1 2 syl3an1 ⊢ F ∈ Fil ⁡ X ∧ S ∈ F ∧ S ∈ Fin → ⋂ F ≠ ∅