Metamath Proof Explorer


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