Theorem: Matroid.Iso.rk_eq (Matroid/Rank.lean)

State before:
α : Type u_1
ι : Type u_2
M N✝ : Matroid α
I B X X' Y Y' Z R : Set α
n : ℕ∞
e✝ f : α
β : Type u_3
N : Matroid β
e : M ≂ N
⊢ M.rk = N.rk
Tactic:
rw [rk, e.erk_eq]
State after:
no goals