Metamath Proof Explorer


Theorem 1cosscnvxrn

Description: Cosets by the converse range Cartesian product. (Contributed by Peter Mazsa, 19-Apr-2020) (Revised by Peter Mazsa, 21-Sep-2021)

Ref Expression
Assertion 1cosscnvxrn A B -1 = A -1 B -1

Proof

Step Hyp Ref Expression
1 br1cosscnvxrn x V y V x A B -1 y x A -1 y x B -1 y
2 1 el2v x A B -1 y x A -1 y x B -1 y
3 2 opabbii x y | x A B -1 y = x y | x A -1 y x B -1 y
4 inopab x y | x A -1 y x y | x B -1 y = x y | x A -1 y x B -1 y
5 3 4 eqtr4i x y | x A B -1 y = x y | x A -1 y x y | x B -1 y
6 relcoss Rel A B -1
7 dfrel4v Rel A B -1 A B -1 = x y | x A B -1 y
8 6 7 mpbi A B -1 = x y | x A B -1 y
9 relcoss Rel A -1
10 dfrel4v Rel A -1 A -1 = x y | x A -1 y
11 9 10 mpbi A -1 = x y | x A -1 y
12 relcoss Rel B -1
13 dfrel4v Rel B -1 B -1 = x y | x B -1 y
14 12 13 mpbi B -1 = x y | x B -1 y
15 11 14 ineq12i A -1 B -1 = x y | x A -1 y x y | x B -1 y
16 5 8 15 3eqtr4i A B -1 = A -1 B -1