Theorem: Matroid.rFin_diff_singleton_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
⊢ M.rFin (X \ {e}) ↔ M.rFin X
Tactic:
rw [(M.rFin_singleton e).rFin_diff_iff]
State after:
no goals