Metamath Proof Explorer


Theorem chrelat3

Description: A consequence of relative atomicity. (Contributed by NM, 2-Jul-2004) (New usage is discouraged.)

Ref Expression
Assertion chrelat3 ⊢ A ∈ C ℋ ∧ B ∈ C ℋ → A ⊆ B ↔ ∀ x ∈ HAtoms x ⊆ A → x ⊆ B

Proof

Step Hyp Ref Expression
1 chrelat2 ⊢ A ∈ C ℋ ∧ B ∈ C ℋ → ¬ A ⊆ B ↔ ∃ x ∈ HAtoms x ⊆ A ∧ ¬ x ⊆ B
2 dfrex2 ⊢ ∃ x ∈ HAtoms x ⊆ A ∧ ¬ x ⊆ B ↔ ¬ ∀ x ∈ HAtoms ¬ x ⊆ A ∧ ¬ x ⊆ B
3 1 2 bitrdi ⊢ A ∈ C ℋ ∧ B ∈ C ℋ → ¬ A ⊆ B ↔ ¬ ∀ x ∈ HAtoms ¬ x ⊆ A ∧ ¬ x ⊆ B
4 3 con4bid ⊢ A ∈ C ℋ ∧ B ∈ C ℋ → A ⊆ B ↔ ∀ x ∈ HAtoms ¬ x ⊆ A ∧ ¬ x ⊆ B
5 iman ⊢ x ⊆ A → x ⊆ B ↔ ¬ x ⊆ A ∧ ¬ x ⊆ B
6 5 ralbii ⊢ ∀ x ∈ HAtoms x ⊆ A → x ⊆ B ↔ ∀ x ∈ HAtoms ¬ x ⊆ A ∧ ¬ x ⊆ B
7 4 6 bitr4di ⊢ A ∈ C ℋ ∧ B ∈ C ℋ → A ⊆ B ↔ ∀ x ∈ HAtoms x ⊆ A → x ⊆ B