-- Mathlib/Topology/Order/IntermediateValue.lean
theorem Continuous.strictMono_of_inj_boundedOrder [BoundedOrder α] {f : α → δ}
    (hf_c : Continuous f) (hf : f ⊥ ≤ f ⊤) (hf_i : Injective f) : StrictMono f

Proof state:
α : Type u
inst✝⁷ : ConditionallyCompleteLinearOrder α
inst✝⁶ : TopologicalSpace α
inst✝⁵ : OrderTopology α
inst✝⁴ : DenselyOrdered α
δ : Type u_1
inst✝³ : LinearOrder δ
inst✝² : TopologicalSpace δ
inst✝¹ : OrderClosedTopology δ
inst✝ : BoundedOrder α
f : α → δ
hf_c : Continuous f
hf : f ⊥ ≤ f ⊤
hf_i : Injective f
⊢ StrictMono f

Tactic:
intro a b hab

Result:
α : Type u
inst✝⁷ : ConditionallyCompleteLinearOrder α
inst✝⁶ : TopologicalSpace α
inst✝⁵ : OrderTopology α
inst✝⁴ : DenselyOrdered α
δ : Type u_1
inst✝³ : LinearOrder δ
inst✝² : TopologicalSpace δ
inst✝¹ : OrderClosedTopology δ
inst✝ : BoundedOrder α
f : α → δ
hf_c : Continuous f
hf : f ⊥ ≤ f ⊤
hf_i : Injective f
a b : α
hab : a < b
⊢ f a < f b

Proof state:
α : Type u
inst✝⁷ : ConditionallyCompleteLinearOrder α
inst✝⁶ : TopologicalSpace α
inst✝⁵ : OrderTopology α
inst✝⁴ : DenselyOrdered α
δ : Type u_1
inst✝³ : LinearOrder δ
inst✝² : TopologicalSpace δ
inst✝¹ : OrderClosedTopology δ
inst✝ : BoundedOrder α
f : α → δ
hf_c : Continuous f
hf : f ⊥ ≤ f ⊤
hf_i : Injective f
a b : α
hab : a < b
h : f b ≤ f a
H : f b < f a
⊢ False

Tactic:
by_cases ha : f a ≤ f ⊥

Result:
case pos
α : Type u
inst✝⁷ : ConditionallyCompleteLinearOrder α
inst✝⁶ : TopologicalSpace α
inst✝⁵ : OrderTopology α
inst✝⁴ : DenselyOrdered α
δ : Type u_1
inst✝³ : LinearOrder δ
inst✝² : TopologicalSpace δ
inst✝¹ : OrderClosedTopology δ
inst✝ : BoundedOrder α
f : α → δ
hf_c : Continuous f
hf : f ⊥ ≤ f ⊤
hf_i : Injective f
a b : α
hab : a < b
h : f b ≤ f a
H : f b < f a
ha : f a ≤ f ⊥
⊢ False

case neg
α : Type u
inst✝⁷ : ConditionallyCompleteLinearOrder α
inst✝⁶ : TopologicalSpace α
inst✝⁵ : OrderTopology α
inst✝⁴ : DenselyOrdered α
δ : Type u_1
inst✝³ : LinearOrder δ
inst✝² : TopologicalSpace δ
inst✝¹ : OrderClosedTopology δ
inst✝ : BoundedOrder α
f : α → δ
hf_c : Continuous f
hf : f ⊥ ≤ f ⊤
hf_i : Injective f
a b : α
hab : a < b
h : f b ≤ f a
H : f b < f a
ha : ¬f a ≤ f ⊥
⊢ False

Proof state:
case pos.intro
α : Type u
inst✝⁷ : ConditionallyCompleteLinearOrder α
inst✝⁶ : TopologicalSpace α
inst✝⁵ : OrderTopology α
inst✝⁴ : DenselyOrdered α
δ : Type u_1
inst✝³ : LinearOrder δ
inst✝² : TopologicalSpace δ
inst✝¹ : OrderClosedTopology δ
inst✝ : BoundedOrder α
f : α → δ
hf_c : Continuous f
hf : f ⊥ ≤ f ⊤
hf_i : Injective f
a b : α
hab : a < b
h : f b ≤ f a
H : f b < f a
ha : ¬f a ≤ f ⊥
hb : f ⊥ < f b
u : α
hu : b ∈ Ioo ⊥ a ∧ f b = f b
⊢ False

Tactic:
exact (hab.trans hu.1.2).false

Result:
no goals

Proof state:
case neg.intro
α : Type u
inst✝⁷ : ConditionallyCompleteLinearOrder α
inst✝⁶ : TopologicalSpace α
inst✝⁵ : OrderTopology α
inst✝⁴ : DenselyOrdered α
δ : Type u_1
inst✝³ : LinearOrder δ
inst✝² : TopologicalSpace δ
inst✝¹ : OrderClosedTopology δ
inst✝ : BoundedOrder α
f : α → δ
hf_c : Continuous f
hf : f ⊥ ≤ f ⊤
hf_i : Injective f
a b : α
hab : a < b
h : f b ≤ f a
H : f b < f a
ha : f ⊥ < f a
hb : f b < f ⊥
u : α
hu : u ∈ Ioo a b ∧ f u = f ⊥
this : u = ⊥
⊢ False

Tactic:
aesop

Result:
no goals

Proof state:
case pos.intro
α : Type u
inst✝⁷ : ConditionallyCompleteLinearOrder α
inst✝⁶ : TopologicalSpace α
inst✝⁵ : OrderTopology α
inst✝⁴ : DenselyOrdered α
δ : Type u_1
inst✝³ : LinearOrder δ
inst✝² : TopologicalSpace δ
inst✝¹ : OrderClosedTopology δ
inst✝ : BoundedOrder α
f : α → δ
hf_c : Continuous f
hf : f ⊥ ≤ f ⊤
hf_i : Injective f
a b : α
hab : a < b
h : f b ≤ f a
H : f b < f a
ha : f a ≤ f ⊥
u : α
hu : u ∈ Ioc b ⊤ ∧ f u = f ⊥
⊢ False

Tactic:
have : u = ⊥ := hf_i hu.2

Result:
case pos.intro
α : Type u
inst✝⁷ : ConditionallyCompleteLinearOrder α
inst✝⁶ : TopologicalSpace α
inst✝⁵ : OrderTopology α
inst✝⁴ : DenselyOrdered α
δ : Type u_1
inst✝³ : LinearOrder δ
inst✝² : TopologicalSpace δ
inst✝¹ : OrderClosedTopology δ
inst✝ : BoundedOrder α
f : α → δ
hf_c : Continuous f
hf : f ⊥ ≤ f ⊤
hf_i : Injective f
a b : α
hab : a < b
h : f b ≤ f a
H : f b < f a
ha : f a ≤ f ⊥
u : α
hu : u ∈ Ioc b ⊤ ∧ f u = f ⊥
this : u = ⊥
⊢ False

Proof state:
case pos
α : Type u
inst✝⁷ : ConditionallyCompleteLinearOrder α
inst✝⁶ : TopologicalSpace α
inst✝⁵ : OrderTopology α
inst✝⁴ : DenselyOrdered α
δ : Type u_1
inst✝³ : LinearOrder δ
inst✝² : TopologicalSpace δ
inst✝¹ : OrderClosedTopology δ
inst✝ : BoundedOrder α
f : α → δ
hf_c : Continuous f
hf : f ⊥ ≤ f ⊤
hf_i : Injective f
a b : α
hab : a < b
h : f b ≤ f a
H : f b < f a
ha : f a ≤ f ⊥
⊢ False

Tactic:
obtain ⟨u, hu⟩ := intermediate_value_Ioc le_top hf_c.continuousOn ⟨H.trans_le ha, hf⟩

Result:
case pos.intro
α : Type u
inst✝⁷ : ConditionallyCompleteLinearOrder α
inst✝⁶ : TopologicalSpace α
inst✝⁵ : OrderTopology α
inst✝⁴ : DenselyOrdered α
δ : Type u_1
inst✝³ : LinearOrder δ
inst✝² : TopologicalSpace δ
inst✝¹ : OrderClosedTopology δ
inst✝ : BoundedOrder α
f : α → δ
hf_c : Continuous f
hf : f ⊥ ≤ f ⊤
hf_i : Injective f
a b : α
hab : a < b
h : f b ≤ f a
H : f b < f a
ha : f a ≤ f ⊥
u : α
hu : u ∈ Ioc b ⊤ ∧ f u = f ⊥
⊢ False

Proof state:
case neg
α : Type u
inst✝⁷ : ConditionallyCompleteLinearOrder α
inst✝⁶ : TopologicalSpace α
inst✝⁵ : OrderTopology α
inst✝⁴ : DenselyOrdered α
δ : Type u_1
inst✝³ : LinearOrder δ
inst✝² : TopologicalSpace δ
inst✝¹ : OrderClosedTopology δ
inst✝ : BoundedOrder α
f : α → δ
hf_c : Continuous f
hf : f ⊥ ≤ f ⊤
hf_i : Injective f
a b : α
hab : a < b
h : f b ≤ f a
H : f b < f a
ha : ¬f a ≤ f ⊥
hb : ¬f ⊥ < f b
⊢ False

Tactic:
push_neg at ha hb

Result:
case neg
α : Type u
inst✝⁷ : ConditionallyCompleteLinearOrder α
inst✝⁶ : TopologicalSpace α
inst✝⁵ : OrderTopology α
inst✝⁴ : DenselyOrdered α
δ : Type u_1
inst✝³ : LinearOrder δ
inst✝² : TopologicalSpace δ
inst✝¹ : OrderClosedTopology δ
inst✝ : BoundedOrder α
f : α → δ
hf_c : Continuous f
hf : f ⊥ ≤ f ⊤
hf_i : Injective f
a b : α
hab : a < b
h : f b ≤ f a
H : f b < f a
ha : f ⊥ < f a
hb : f b ≤ f ⊥
⊢ False

Proof state:
case pos.intro
α : Type u
inst✝⁷ : ConditionallyCompleteLinearOrder α
inst✝⁶ : TopologicalSpace α
inst✝⁵ : OrderTopology α
inst✝⁴ : DenselyOrdered α
δ : Type u_1
inst✝³ : LinearOrder δ
inst✝² : TopologicalSpace δ
inst✝¹ : OrderClosedTopology δ
inst✝ : BoundedOrder α
f : α → δ
hf_c : Continuous f
hf : f ⊥ ≤ f ⊤
hf_i : Injective f
a b : α
hab : a < b
h : f b ≤ f a
H : f b < f a
ha : f a ≤ f ⊥
u : α
hu : u ∈ Ioc b ⊤ ∧ f u = f ⊥
this : u = ⊥
⊢ False

Tactic:
aesop

Result:
no goals