Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - add the Axiom of Union
Weak dominance
relwdom
Next ⟩
brwdom
Metamath Proof Explorer
Ascii
Structured
Theorem
relwdom
Description:
Weak dominance is a relation.
(Contributed by
Stefan O'Rear
, 11-Feb-2015)
Ref
Expression
Assertion
relwdom
⊢
Rel ≼
*
Proof
Step
Hyp
Ref
Expression
1
df-wdom
⊢
≼
*
= { 〈
𝑥
,
𝑦
〉 ∣ (
𝑥
= ∅ ∨ ∃
𝑧
𝑧
:
𝑦
–
onto
→
𝑥
) }
2
1
relopabiv
⊢
Rel ≼
*