Theorem: Matroid.Loop.er_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
he : M.Loop e
⊢ M.er {e} = 0
Tactic:
rw [← er_cl_eq, he.cl, er_cl_eq, er_empty]
State after:
no goals