Theorem: Stream'.WSeq.LiftRel.trans
File: Mathlib/Data/Seq/WSeq.lean

tactic: refine' ⟨fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u, ⟨t, h1, h2⟩, fun {s u} h => _⟩
state_before: α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s t u : WSeq α
h1 : LiftRel R s t
h2 : LiftRel R t u
⊢ LiftRel R s u

tactic: rcases h with ⟨t, h1, h2⟩
state_before: α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t u✝ : WSeq α
h1 : LiftRel R s✝ t
h2 : LiftRel R t u✝
s u : WSeq α
h : (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) s u
⊢ Computation.LiftRel (LiftRelO R fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (destruct s) (destruct u)

tactic: have h1 := liftRel_destruct h1
state_before: case intro.intro
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝ : LiftRel R s✝ t✝
h2✝ : LiftRel R t✝ u✝
s u t : WSeq α
h1 : LiftRel R s t
h2 : LiftRel R t u
⊢ Computation.LiftRel (LiftRelO R fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (destruct s) (destruct u)

tactic: have h2 := liftRel_destruct h2
state_before: case intro.intro
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2 : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
⊢ Computation.LiftRel (LiftRelO R fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (destruct s) (destruct u)

tactic: refine'
  Computation.liftRel_def.2
    ⟨(Computation.terminates_of_LiftRel h1).trans (Computation.terminates_of_LiftRel h2),
      fun {a c} ha hc => _⟩
state_before: case intro.intro
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝¹ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
⊢ Computation.LiftRel (LiftRelO R fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (destruct s) (destruct u)

tactic: rcases h1.left ha with ⟨b, hb, t1⟩
state_before: case intro.intro
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝¹ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
a c : Option (α × WSeq α)
ha : a ∈ destruct s
hc : c ∈ destruct u
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) a c

tactic: have t2 := Computation.rel_of_LiftRel h2 hb hc
state_before: case intro.intro.intro.intro
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝¹ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
a c : Option (α × WSeq α)
ha : a ∈ destruct s
hc : c ∈ destruct u
b : Option (α × WSeq α)
hb : b ∈ destruct t
t1 : LiftRelO R (LiftRel R) a b
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) a c

tactic: cases' a with a <;> cases' c with c
state_before: case intro.intro.intro.intro
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝¹ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
a c : Option (α × WSeq α)
ha : a ∈ destruct s
hc : c ∈ destruct u
b : Option (α × WSeq α)
hb : b ∈ destruct t
t1 : LiftRelO R (LiftRel R) a b
t2 : LiftRelO R (LiftRel R) b c
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) a c

tactic: trivial
state_before: case intro.intro.intro.intro.none.none
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝¹ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
b : Option (α × WSeq α)
hb : b ∈ destruct t
ha : none ∈ destruct s
t1 : LiftRelO R (LiftRel R) none b
hc : none ∈ destruct u
t2 : LiftRelO R (LiftRel R) b none
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) none none

tactic: cases b
state_before: case intro.intro.intro.intro.none.some
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝¹ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
b : Option (α × WSeq α)
hb : b ∈ destruct t
ha : none ∈ destruct s
t1 : LiftRelO R (LiftRel R) none b
c : α × WSeq α
hc : some c ∈ destruct u
t2 : LiftRelO R (LiftRel R) b (some c)
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) none (some c)

tactic: cases t2
state_before: case intro.intro.intro.intro.none.some.none
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝¹ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
ha : none ∈ destruct s
c : α × WSeq α
hc : some c ∈ destruct u
hb : none ∈ destruct t
t1 : LiftRelO R (LiftRel R) none none
t2 : LiftRelO R (LiftRel R) none (some c)
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) none (some c)

tactic: cases t1
state_before: case intro.intro.intro.intro.none.some.some
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝¹ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
ha : none ∈ destruct s
c : α × WSeq α
hc : some c ∈ destruct u
val✝ : α × WSeq α
hb : some val✝ ∈ destruct t
t1 : LiftRelO R (LiftRel R) none (some val✝)
t2 : LiftRelO R (LiftRel R) (some val✝) (some c)
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) none (some c)

tactic: cases a
state_before: case intro.intro.intro.intro.some.none
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝¹ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
b : Option (α × WSeq α)
hb : b ∈ destruct t
a : α × WSeq α
ha : some a ∈ destruct s
t1 : LiftRelO R (LiftRel R) (some a) b
hc : none ∈ destruct u
t2 : LiftRelO R (LiftRel R) b none
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (some a) none

tactic: cases' b with b
state_before: case intro.intro.intro.intro.some.none.mk
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝¹ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
b : Option (α × WSeq α)
hb : b ∈ destruct t
hc : none ∈ destruct u
t2 : LiftRelO R (LiftRel R) b none
fst✝ : α
snd✝ : WSeq α
ha : some (fst✝, snd✝) ∈ destruct s
t1 : LiftRelO R (LiftRel R) (some (fst✝, snd✝)) b
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (some (fst✝, snd✝)) none

tactic: cases t1
state_before: case intro.intro.intro.intro.some.none.mk.none
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝¹ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
hc : none ∈ destruct u
fst✝ : α
snd✝ : WSeq α
ha : some (fst✝, snd✝) ∈ destruct s
hb : none ∈ destruct t
t2 : LiftRelO R (LiftRel R) none none
t1 : LiftRelO R (LiftRel R) (some (fst✝, snd✝)) none
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (some (fst✝, snd✝)) none

tactic: cases b
state_before: case intro.intro.intro.intro.some.none.mk.some
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝¹ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
hc : none ∈ destruct u
fst✝ : α
snd✝ : WSeq α
ha : some (fst✝, snd✝) ∈ destruct s
b : α × WSeq α
hb : some b ∈ destruct t
t2 : LiftRelO R (LiftRel R) (some b) none
t1 : LiftRelO R (LiftRel R) (some (fst✝, snd✝)) (some b)
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (some (fst✝, snd✝)) none

tactic: cases t2
state_before: case intro.intro.intro.intro.some.none.mk.some.mk
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝¹ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
hc : none ∈ destruct u
fst✝¹ : α
snd✝¹ : WSeq α
ha : some (fst✝¹, snd✝¹) ∈ destruct s
fst✝ : α
snd✝ : WSeq α
hb : some (fst✝, snd✝) ∈ destruct t
t2 : LiftRelO R (LiftRel R) (some (fst✝, snd✝)) none
t1 : LiftRelO R (LiftRel R) (some (fst✝¹, snd✝¹)) (some (fst✝, snd✝))
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (some (fst✝¹, snd✝¹)) none

tactic: cases' a with a s
state_before: case intro.intro.intro.intro.some.some
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝ t✝
h2✝¹ : LiftRel R t✝ u✝
s u t : WSeq α
h1✝ : LiftRel R s t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
b : Option (α × WSeq α)
hb : b ∈ destruct t
a : α × WSeq α
ha : some a ∈ destruct s
t1 : LiftRelO R (LiftRel R) (some a) b
c : α × WSeq α
hc : some c ∈ destruct u
t2 : LiftRelO R (LiftRel R) b (some c)
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (some a) (some c)

tactic: cases' b with b
state_before: case intro.intro.intro.intro.some.some.mk
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝¹ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝¹ t✝
h2✝¹ : LiftRel R t✝ u✝
s✝ u t : WSeq α
h1✝ : LiftRel R s✝ t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s✝) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
b : Option (α × WSeq α)
hb : b ∈ destruct t
c : α × WSeq α
hc : some c ∈ destruct u
t2 : LiftRelO R (LiftRel R) b (some c)
a : α
s : WSeq α
ha : some (a, s) ∈ destruct s✝
t1 : LiftRelO R (LiftRel R) (some (a, s)) b
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (some (a, s)) (some c)

tactic: cases' b with b t
state_before: case intro.intro.intro.intro.some.some.mk.some
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝¹ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝¹ t✝
h2✝¹ : LiftRel R t✝ u✝
s✝ u t : WSeq α
h1✝ : LiftRel R s✝ t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s✝) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
c : α × WSeq α
hc : some c ∈ destruct u
a : α
s : WSeq α
ha : some (a, s) ∈ destruct s✝
b : α × WSeq α
hb : some b ∈ destruct t
t2 : LiftRelO R (LiftRel R) (some b) (some c)
t1 : LiftRelO R (LiftRel R) (some (a, s)) (some b)
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (some (a, s)) (some c)

tactic: cases' c with c u
state_before: case intro.intro.intro.intro.some.some.mk.some.mk
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝¹ t✝¹ u✝ : WSeq α
h1✝¹ : LiftRel R s✝¹ t✝¹
h2✝¹ : LiftRel R t✝¹ u✝
s✝ u t✝ : WSeq α
h1✝ : LiftRel R s✝ t✝
h2✝ : LiftRel R t✝ u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s✝) (destruct t✝)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t✝) (destruct u)
c : α × WSeq α
hc : some c ∈ destruct u
a : α
s : WSeq α
ha : some (a, s) ∈ destruct s✝
b : α
t : WSeq α
hb : some (b, t) ∈ destruct t✝
t2 : LiftRelO R (LiftRel R) (some (b, t)) (some c)
t1 : LiftRelO R (LiftRel R) (some (a, s)) (some (b, t))
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (some (a, s)) (some c)

tactic: cases' t1 with ab st
state_before: case intro.intro.intro.intro.some.some.mk.some.mk.mk
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝¹ t✝¹ u✝¹ : WSeq α
h1✝¹ : LiftRel R s✝¹ t✝¹
h2✝¹ : LiftRel R t✝¹ u✝¹
s✝ u✝ t✝ : WSeq α
h1✝ : LiftRel R s✝ t✝
h2✝ : LiftRel R t✝ u✝
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s✝) (destruct t✝)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t✝) (destruct u✝)
a : α
s : WSeq α
ha : some (a, s) ∈ destruct s✝
b : α
t : WSeq α
hb : some (b, t) ∈ destruct t✝
t1 : LiftRelO R (LiftRel R) (some (a, s)) (some (b, t))
c : α
u : WSeq α
hc : some (c, u) ∈ destruct u✝
t2 : LiftRelO R (LiftRel R) (some (b, t)) (some (c, u))
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (some (a, s)) (some (c, u))

tactic: cases' t2 with bc tu
state_before: case intro.intro.intro.intro.some.some.mk.some.mk.mk.intro
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝¹ t✝¹ u✝¹ : WSeq α
h1✝¹ : LiftRel R s✝¹ t✝¹
h2✝¹ : LiftRel R t✝¹ u✝¹
s✝ u✝ t✝ : WSeq α
h1✝ : LiftRel R s✝ t✝
h2✝ : LiftRel R t✝ u✝
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s✝) (destruct t✝)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t✝) (destruct u✝)
a : α
s : WSeq α
ha : some (a, s) ∈ destruct s✝
b : α
t : WSeq α
hb : some (b, t) ∈ destruct t✝
c : α
u : WSeq α
hc : some (c, u) ∈ destruct u✝
t2 : LiftRelO R (LiftRel R) (some (b, t)) (some (c, u))
ab : R a b
st : LiftRel R s t
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (some (a, s)) (some (c, u))

tactic: exact ⟨H ab bc, t, st, tu⟩
state_before: case intro.intro.intro.intro.some.some.mk.some.mk.mk.intro.intro
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝¹ t✝¹ u✝¹ : WSeq α
h1✝¹ : LiftRel R s✝¹ t✝¹
h2✝¹ : LiftRel R t✝¹ u✝¹
s✝ u✝ t✝ : WSeq α
h1✝ : LiftRel R s✝ t✝
h2✝ : LiftRel R t✝ u✝
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s✝) (destruct t✝)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t✝) (destruct u✝)
a : α
s : WSeq α
ha : some (a, s) ∈ destruct s✝
b : α
t : WSeq α
hb : some (b, t) ∈ destruct t✝
c : α
u : WSeq α
hc : some (c, u) ∈ destruct u✝
ab : R a b
st : LiftRel R s t
bc : R b c
tu : LiftRel R t u
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (some (a, s)) (some (c, u))

tactic: cases t1
state_before: case intro.intro.intro.intro.some.some.mk.none
α : Type u
β : Type v
γ : Type w
R : α → α → Prop
H : Transitive R
s✝¹ t✝ u✝ : WSeq α
h1✝¹ : LiftRel R s✝¹ t✝
h2✝¹ : LiftRel R t✝ u✝
s✝ u t : WSeq α
h1✝ : LiftRel R s✝ t
h2✝ : LiftRel R t u
h1 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct s✝) (destruct t)
h2 : Computation.LiftRel (LiftRelO R (LiftRel R)) (destruct t) (destruct u)
c : α × WSeq α
hc : some c ∈ destruct u
a : α
s : WSeq α
ha : some (a, s) ∈ destruct s✝
hb : none ∈ destruct t
t2 : LiftRelO R (LiftRel R) none (some c)
t1 : LiftRelO R (LiftRel R) (some (a, s)) none
⊢ LiftRelO R (fun s u => ∃ t, LiftRel R s t ∧ LiftRel R t u) (some (a, s)) (some c)