Database
SUPPLEMENTARY MATERIAL (USERS' MATHBOXES)
Mathbox for Zhi Wang
ZF Set Theory - add the Axiom of Union
Function transposition
tposid
Next ⟩
tposidres
Metamath Proof Explorer
Ascii
Unicode
Theorem
tposid
Description:
Swap an ordered pair.
(Contributed by
Zhi Wang
, 5-Oct-2025)
Ref
Expression
Assertion
tposid
⊢
X
tpos
I
Y
=
Y
X
Proof
Step
Hyp
Ref
Expression
1
ovtpos
⊢
X
tpos
I
Y
=
Y
I
X
2
df-ov
⊢
Y
I
X
=
I
⁡
Y
X
3
opex
⊢
Y
X
∈
V
4
fvi
⊢
Y
X
∈
V
→
I
⁡
Y
X
=
Y
X
5
3
4
ax-mp
⊢
I
⁡
Y
X
=
Y
X
6
1
2
5
3eqtri
⊢
X
tpos
I
Y
=
Y
X