Theorem: Matroid.er_le_er_iff (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
inst✝ : M.FiniteRk
⊢ M.er X ≤ M.er Y ↔ M.r X ≤ M.r Y
Tactic:
rw [← coe_r_eq, ← coe_r_eq, Nat.cast_le]
State after:
no goals