exact Or.inl rfl
case refine_2.mk.inl
α : Type u_1
M : Matroid α
I F✝ X Y F' F₁ F₂ P L H H₁ H₂ H' B C K : Set α
e f : α
hF₁ : M.Flat F₁
F : Set α
hF : M.Flat F
h₁ : F ⊆ F₁
x✝ : M.Flat F ∧ M.Flat F₁ ∧ F ⊂ F₁ ∧ ∀ (F_1 : Set α), M.Flat F_1 → F ⊆ F_1 → F_1 ⊆ F₁ → F_1 = F ∨ F_1 = F₁
hF₀ : M.Flat F
hss : F ⊂ F₁
hforall : ∀ (F_1 : Set α), M.Flat F_1 → F ⊆ F_1 → F_1 ⊆ F₁ → F_1 = F ∨ F_1 = F₁
h₀ : F ⊆ F
⊢ ⟨F, hF⟩ = ⋯.toFlatOf ∨ ⟨F, hF⟩ = ⋯.toFlatOf
no goals