case a
ι : Type ?u.30542
α : Type u_1
inst✝² : Preorder α
inst✝¹ : LocallyFiniteOrder α
a a₁ a₂ b b₁ b₂ c x✝ : α
inst✝ : DecidablePred fun x => x < c
hcb : c ≤ b
x : α
⊢ x ∈ filter (fun x => x < c) (Ico a b) ↔ x ∈ Ico a c
ι : Type ?u.30542
α : Type u_1
inst✝² : Preorder α
inst✝¹ : LocallyFiniteOrder α
a a₁ a₂ b b₁ b₂ c x : α
inst✝ : DecidablePred fun x => x < c
hcb : c ≤ b
⊢ filter (fun x => x < c) (Ico a b) = Ico a c
ext x
case a
ι : Type ?u.30542
α : Type u_1
inst✝² : Preorder α
inst✝¹ : LocallyFiniteOrder α
a a₁ a₂ b b₁ b₂ c x✝ : α
inst✝ : DecidablePred fun x => x < c
hcb : c ≤ b
x : α
⊢ (a ≤ x ∧ x < c) ∧ x < b ↔ a ≤ x ∧ x < c
case a
ι : Type ?u.30542
α : Type u_1
inst✝² : Preorder α
inst✝¹ : LocallyFiniteOrder α
a a₁ a₂ b b₁ b₂ c x✝ : α
inst✝ : DecidablePred fun x => x < c
hcb : c ≤ b
x : α
⊢ x ∈ filter (fun x => x < c) (Ico a b) ↔ x ∈ Ico a c
rw [mem_filter, mem_Ico, mem_Ico, and_right_comm]
no goals
case a
ι : Type ?u.30542
α : Type u_1
inst✝² : Preorder α
inst✝¹ : LocallyFiniteOrder α
a a₁ a₂ b b₁ b₂ c x✝ : α
inst✝ : DecidablePred fun x => x < c
hcb : c ≤ b
x : α
⊢ (a ≤ x ∧ x < c) ∧ x < b ↔ a ≤ x ∧ x < c
exact and_iff_left_of_imp fun h => h.2.trans_le hcb