Metamath Proof Explorer


Theorem eldisjssi

Description: Subclass theorem for disjoint elementhood, inference version. (Contributed by Peter Mazsa, 28-Sep-2021)

Ref Expression
Hypothesis eldisjssi.1 ⊢ A ⊆ B
Assertion eldisjssi ⊢ ElDisj B → ElDisj A

Proof

Step Hyp Ref Expression
1 eldisjssi.1 ⊢ A ⊆ B
2 eldisjss ⊢ A ⊆ B → ElDisj B → ElDisj A
3 1 2 ax-mp ⊢ ElDisj B → ElDisj A