Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - add the Axiom of Union
Equinumerosity
reldom
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relsdom
Metamath Proof Explorer
Ascii
Structured
Theorem
reldom
Description:
Dominance is a relation.
(Contributed by
NM
, 28-Mar-1998)
Ref
Expression
Assertion
reldom
⊢
Rel ≼
Proof
Step
Hyp
Ref
Expression
1
df-dom
⊢
≼ = { 〈
𝑥
,
𝑦
〉 ∣ ∃
𝑓
𝑓
:
𝑥
–
1-1
→
𝑦
}
2
1
relopabiv
⊢
Rel ≼