refine ⟨fun ⟨e⟩ ↦ ⟨by simpa using e.rk_le, by simpa using IsoMinor.rk_le e.dual⟩, fun h ↦ ?_⟩
α : Type u_1
M : Matroid α
E I B X C : Set α
k : ℕ∞
a b a' b' a₁ a₂ d₁ d₂ : ℕ
⊢ Nonempty (unif a₁ (a₁ + d₁) ≤i unif a₂ (a₂ + d₂)) ↔ a₁ ≤ a₂ ∧ d₁ ≤ d₂
α : Type u_1
M : Matroid α
E I B X C : Set α
k : ℕ∞
a b a' b' a₁ a₂ d₁ d₂ : ℕ
h : a₁ ≤ a₂ ∧ d₁ ≤ d₂
⊢ Nonempty (unif a₁ (a₁ + d₁) ≤i unif a₂ (a₂ + d₂))