Metamath Proof Explorer


Theorem cnvcosseq

Description: The converse of cosets by R are cosets by R . (Contributed by Peter Mazsa, 3-May-2019)

Ref Expression
Assertion cnvcosseq ⊢ ≀ R -1 = ≀ R

Proof

Step Hyp Ref Expression
1 brcosscnvcoss ⊢ x ∈ V ∧ y ∈ V → x ≀ R y ↔ y ≀ R x
2 1 el2v ⊢ x ≀ R y ↔ y ≀ R x
3 2 biimpi ⊢ x ≀ R y → y ≀ R x
4 3 gen2 ⊢ ∀ x ∀ y x ≀ R y → y ≀ R x
5 cnvsym ⊢ ≀ R -1 ⊆ ≀ R ↔ ∀ x ∀ y x ≀ R y → y ≀ R x
6 4 5 mpbir ⊢ ≀ R -1 ⊆ ≀ R
7 relcoss ⊢ Rel ⁡ ≀ R
8 relcnveq ⊢ Rel ⁡ ≀ R → ≀ R -1 ⊆ ≀ R ↔ ≀ R -1 = ≀ R
9 7 8 ax-mp ⊢ ≀ R -1 ⊆ ≀ R ↔ ≀ R -1 = ≀ R
10 6 9 mpbi ⊢ ≀ R -1 = ≀ R