Metamath Proof Explorer


Theorem 0wdom

Description: Any set weakly dominates the empty set. (Contributed by Stefan O'Rear, 11-Feb-2015)

Ref Expression
Assertion 0wdom ( 𝑋 ∈ 𝑉 → ∅ ≼* 𝑋 )

Proof

Step Hyp Ref Expression
1 eqid ⊢ ∅ = ∅
2 1 orci ⊢ ( ∅ = ∅ ∨ ∃ 𝑧 𝑧 : 𝑋 –onto→ ∅ )
3 brwdom ⊢ ( 𝑋 ∈ 𝑉 → ( ∅ ≼* 𝑋 ↔ ( ∅ = ∅ ∨ ∃ 𝑧 𝑧 : 𝑋 –onto→ ∅ ) ) )
4 2 3 mpbiri ⊢ ( 𝑋 ∈ 𝑉 → ∅ ≼* 𝑋 )