Theorem: Matroid.rk_def (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
M : Matroid α
⊢ M.rk = M.r M.E
Tactic:
rw [rk,r,er,restrict_ground_eq_self]
State after:
no goals