Metamath Proof Explorer


Theorem chm1i

Description: Meet with lattice one in CH . (Contributed by NM, 24-Oct-1999) (New usage is discouraged.)

Ref Expression
Hypothesis ch0le.1 ⊢ A ∈ C ℋ
Assertion chm1i ⊢ A ∩ ℋ = A

Proof

Step Hyp Ref Expression
1 ch0le.1 ⊢ A ∈ C ℋ
2 1 chssii ⊢ A ⊆ ℋ
3 dfss2 ⊢ A ⊆ ℋ ↔ A ∩ ℋ = A
4 2 3 mpbi ⊢ A ∩ ℋ = A