Metamath Proof Explorer


Theorem bj-restsn10

Description: Special case of bj-restsn , bj-restsnss , and bj-rest10 . (Contributed by BJ, 27-Apr-2021)

Ref Expression
Assertion bj-restsn10 ( 𝑋𝑉 → ( { 𝑋 } ↾t ∅ ) = { ∅ } )

Proof

Step Hyp Ref Expression
1 0ss ∅ ⊆ 𝑋
2 bj-restsnss ( ( 𝑋𝑉 ∧ ∅ ⊆ 𝑋 ) → ( { 𝑋 } ↾t ∅ ) = { ∅ } )
3 1 2 mpan2 ( 𝑋𝑉 → ( { 𝑋 } ↾t ∅ ) = { ∅ } )