l m✝ n✝ : ℕ
α : Type u_1
β : Type ?u.4399
m n : ℕ
P : Matrix (Fin (m + 1)) (Fin n) α → Prop
⊢ (∃ x x_1, P (↑of (vecCons x x_1))) ↔ ∃ x, P x
l m✝ n✝ : ℕ
α : Type u_1
β : Type ?u.4399
m n : ℕ
P : Matrix (Fin (m + 1)) (Fin n) α → Prop
⊢ Exists P ↔ ∃ x, P x
simp only [Exists, FinVec.exists_iff, exists_iff]
no goals
l m✝ n✝ : ℕ
α : Type u_1
β : Type ?u.4399
m n : ℕ
P : Matrix (Fin (m + 1)) (Fin n) α → Prop
⊢ (∃ x x_1, P (↑of (vecCons x x_1))) ↔ ∃ x, P x
exact Iff.symm Fin.exists_fin_succ_pi