Theorem: Matroid.relRank_eq_zero_of_subset (Matroid/Minor/Rank.lean)

State before:
α : Type u_1
M✝ N : Matroid α
I J C D X Y Z : Set α
e f : α
M : Matroid α
h : Y ⊆ X
⊢ M.relRank X Y = 0
Tactic:
rw [relRank_eq_diff_right, diff_eq_empty.2 h, relRank_empty_right]
State after:
no goals