exact Or.inl ⟨rfl,rfl⟩
case inl.intro
α : Type u_1
β : Type u_2
γ : Type u_3
α₁ : Type u_4
α₂ : Type u_5
α₃ : Type u_6
M : Matroid α
N : Matroid β
B I D X Y : Set α
⊢ emptyOn α = emptyOn α ∧ emptyOn β = emptyOn β ∨ Nonempty α ∧ Nonempty β ∧ Nonempty ((emptyOn α).Iso (emptyOn β))
no goals