case intro
α : Type u_1
s✝ : Set α
inst✝ : ConditionallyCompleteLinearOrder α
s : Set α
hs : OrdConnected s
t : Set ↑s
h_bdd : BddBelow t
c : ↑s
hct : c ∈ t
⊢ sInf (Subtype.val '' t) ∈ s
α : Type u_1
s✝ : Set α
inst✝ : ConditionallyCompleteLinearOrder α
s : Set α
hs : OrdConnected s
t : Set ↑s
ht : Set.Nonempty t
h_bdd : BddBelow t
⊢ sInf (Subtype.val '' t) ∈ s
obtain ⟨c, hct⟩ : ∃ c, c ∈ t := ht
case intro.intro
α : Type u_1
s✝ : Set α
inst✝ : ConditionallyCompleteLinearOrder α
s : Set α
hs : OrdConnected s
t : Set ↑s
c : ↑s
hct : c ∈ t
B : ↑s
hB : B ∈ lowerBounds t
⊢ sInf (Subtype.val '' t) ∈ s
case intro
α : Type u_1
s✝ : Set α
inst✝ : ConditionallyCompleteLinearOrder α
s : Set α
hs : OrdConnected s
t : Set ↑s
h_bdd : BddBelow t
c : ↑s
hct : c ∈ t
⊢ sInf (Subtype.val '' t) ∈ s
obtain ⟨B, hB⟩ : ∃ B, B ∈ lowerBounds t := h_bdd
case intro.intro.refine'_1
α : Type u_1
s✝ : Set α
inst✝ : ConditionallyCompleteLinearOrder α
s : Set α
hs : OrdConnected s
t : Set ↑s
c : ↑s
hct : c ∈ t
B : ↑s
hB : B ∈ lowerBounds t
⊢ ↑B ≤ sInf (Subtype.val '' t)

case intro.intro.refine'_2
α : Type u_1
s✝ : Set α
inst✝ : ConditionallyCompleteLinearOrder α
s : Set α
hs : OrdConnected s
t : Set ↑s
c : ↑s
hct : c ∈ t
B : ↑s
hB : B ∈ lowerBounds t
⊢ sInf (Subtype.val '' t) ≤ ↑c
case intro.intro
α : Type u_1
s✝ : Set α
inst✝ : ConditionallyCompleteLinearOrder α
s : Set α
hs : OrdConnected s
t : Set ↑s
c : ↑s
hct : c ∈ t
B : ↑s
hB : B ∈ lowerBounds t
⊢ sInf (Subtype.val '' t) ∈ s
refine' hs.out B.2 c.2 ⟨_, _⟩
no goals
case intro.intro.refine'_1
α : Type u_1
s✝ : Set α
inst✝ : ConditionallyCompleteLinearOrder α
s : Set α
hs : OrdConnected s
t : Set ↑s
c : ↑s
hct : c ∈ t
B : ↑s
hB : B ∈ lowerBounds t
⊢ ↑B ≤ sInf (Subtype.val '' t)
exact (Subtype.mono_coe s).le_csInf_image ⟨c, hct⟩ hB
no goals
case intro.intro.refine'_2
α : Type u_1
s✝ : Set α
inst✝ : ConditionallyCompleteLinearOrder α
s : Set α
hs : OrdConnected s
t : Set ↑s
c : ↑s
hct : c ∈ t
B : ↑s
hB : B ∈ lowerBounds t
⊢ sInf (Subtype.val '' t) ≤ ↑c
exact (Subtype.mono_coe s).csInf_image_le hct ⟨B, hB⟩