Theorem: Profinite.NobelingProof.GoodProducts.chain'_cons_of_lt
File: Mathlib/Topology/Category/Profinite/Nobeling.lean

Proof steps:
state_before: I : Type u
inst✝¹ : LinearOrder I
inst✝ : IsWellOrder I fun x x_1 => x < x_1
C : Set (I → Bool)
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x x_1 => x < x_1
l : ↑(MaxProducts C ho)
q : Products I
hq : q < (↑l).Tail
⊢ List.Chain' (fun x x_1 => x > x_1) (term I ho :: ↑q)
state_after: I : Type u
inst✝¹ : LinearOrder I
inst✝ : IsWellOrder I fun x x_1 => x < x_1
C : Set (I → Bool)
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x x_1 => x < x_1
l : ↑(MaxProducts C ho)
q : Products I
hq : q < (↑l).Tail
this : Inhabited I
⊢ List.Chain' (fun x x_1 => x > x_1) (term I ho :: ↑q)
tactic: have : Inhabited I := ⟨term I ho⟩
state_before: I : Type u
inst✝¹ : LinearOrder I
inst✝ : IsWellOrder I fun x x_1 => x < x_1
C : Set (I → Bool)
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x x_1 => x < x_1
l : ↑(MaxProducts C ho)
q : Products I
hq : q < (↑l).Tail
this : Inhabited I
⊢ List.Chain' (fun x x_1 => x > x_1) (term I ho :: ↑q)
state_after: I : Type u
inst✝¹ : LinearOrder I
inst✝ : IsWellOrder I fun x x_1 => x < x_1
C : Set (I → Bool)
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x x_1 => x < x_1
l : ↑(MaxProducts C ho)
q : Products I
hq : q < (↑l).Tail
this : Inhabited I
⊢ List.Pairwise (fun x x_1 => x > x_1) (term I ho :: ↑q)
tactic: rw [List.chain'_iff_pairwise]
state_before: I : Type u
inst✝¹ : LinearOrder I
inst✝ : IsWellOrder I fun x x_1 => x < x_1
C : Set (I → Bool)
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x x_1 => x < x_1
l : ↑(MaxProducts C ho)
q : Products I
hq : q < (↑l).Tail
this : Inhabited I
⊢ List.Pairwise (fun x x_1 => x > x_1) (term I ho :: ↑q)
state_after: I : Type u
inst✝¹ : LinearOrder I
inst✝ : IsWellOrder I fun x x_1 => x < x_1
C : Set (I → Bool)
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x x_1 => x < x_1
l : ↑(MaxProducts C ho)
q : Products I
hq : q < (↑l).Tail
this : Inhabited I
⊢ (∀ a' ∈ ↑q, a' < term I ho) ∧ List.Pairwise (fun x x_1 => x_1 < x) ↑q
tactic: simp only [gt_iff_lt, List.pairwise_cons]
state_before: I : Type u
inst✝¹ : LinearOrder I
inst✝ : IsWellOrder I fun x x_1 => x < x_1
C : Set (I → Bool)
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x x_1 => x < x_1
l : ↑(MaxProducts C ho)
q : Products I
hq : q < (↑l).Tail
this : Inhabited I
⊢ (∀ a' ∈ ↑q, a' < term I ho) ∧ List.Pairwise (fun x x_1 => x_1 < x) ↑q
state_after: I : Type u
inst✝¹ : LinearOrder I
inst✝ : IsWellOrder I fun x x_1 => x < x_1
C : Set (I → Bool)
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x x_1 => x < x_1
l : ↑(MaxProducts C ho)
q : Products I
hq : q < (↑l).Tail
this : Inhabited I
a : I
ha : a ∈ ↑q
⊢ (↑q).head! < term I ho
tactic: refine ⟨fun a ha ↦ lt_of_le_of_lt (Products.rel_head!_of_mem ha) ?_,
    List.chain'_iff_pairwise.mp q.prop⟩
state_before: I : Type u
inst✝¹ : LinearOrder I
inst✝ : IsWellOrder I fun x x_1 => x < x_1
C : Set (I → Bool)
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x x_1 => x < x_1
l : ↑(MaxProducts C ho)
q : Products I
hq : q < (↑l).Tail
this : Inhabited I
a : I
ha : a ∈ ↑q
⊢ (↑q).head! < term I ho
state_after: I : Type u
inst✝¹ : LinearOrder I
inst✝ : IsWellOrder I fun x x_1 => x < x_1
C : Set (I → Bool)
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x x_1 => x < x_1
l : ↑(MaxProducts C ho)
q : Products I
hq : q < (↑l).Tail
this : Inhabited I
a : I
ha : a ∈ ↑q
⊢ (↑(↑l).Tail).head! < term I ho
tactic: refine lt_of_le_of_lt (Products.head!_le_of_lt hq (q.val.ne_nil_of_mem ha)) ?_
state_before: I : Type u
inst✝¹ : LinearOrder I
inst✝ : IsWellOrder I fun x x_1 => x < x_1
C : Set (I → Bool)
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x x_1 => x < x_1
l : ↑(MaxProducts C ho)
q : Products I
hq : q < (↑l).Tail
this : Inhabited I
a : I
ha : a ∈ ↑q
⊢ (↑(↑l).Tail).head! < term I ho
state_after: case pos
I : Type u
inst✝¹ : LinearOrder I
inst✝ : IsWellOrder I fun x x_1 => x < x_1
C : Set (I → Bool)
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x x_1 => x < x_1
l : ↑(MaxProducts C ho)
q : Products I
hq : q < (↑l).Tail
this : Inhabited I
a : I
ha : a ∈ ↑q
hM : ↑(↑l).Tail = []
⊢ (↑(↑l).Tail).head! < term I ho

case neg
I : Type u
inst✝¹ : LinearOrder I
inst✝ : IsWellOrder I fun x x_1 => x < x_1
C : Set (I → Bool)
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x x_1 => x < x_1
l : ↑(MaxProducts C ho)
q : Products I
hq : q < (↑l).Tail
this : Inhabited I
a : I
ha : a ∈ ↑q
hM : ¬↑(↑l).Tail = []
⊢ (↑(↑l).Tail).head! < term I ho
tactic: by_cases hM : l.val.Tail.val = []