Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - add the Axiom of Power Sets
Derive the Axiom of Pairing
otex
Next ⟩
elopg
Metamath Proof Explorer
Ascii
Unicode
Theorem
otex
Description:
An ordered triple of classes is a set.
(Contributed by
NM
, 3-Apr-2015)
Ref
Expression
Assertion
otex
⊢
A
B
C
∈
V
Proof
Step
Hyp
Ref
Expression
1
df-ot
⊢
A
B
C
=
A
B
C
2
opex
⊢
A
B
C
∈
V
3
1
2
eqeltri
⊢
A
B
C
∈
V