-- Mathlib/Probability/Moments/Basic.lean
theorem mgf_pos' (hμ : μ ≠ 0) (h_int_X : Integrable (fun ω => exp (t * X ω)) μ) :
    0 < mgf X μ t

Proof state:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
h_eq_univ : (Function.support fun x => rexp (t * X x)) = Set.univ
⊢ 0 < μ ((Function.support fun x => rexp (t * X x)) ∩ Set.univ)

Tactic:
rw [h_eq_univ, Set.inter_univ _]

Result:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
h_eq_univ : (Function.support fun x => rexp (t * X x)) = Set.univ
⊢ 0 < μ Set.univ

Proof state:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
⊢ 0 < ∫ (x : Ω), rexp (t * X x) ∂μ

Tactic:
have : ∫ x : Ω, exp (t * X x) ∂μ = ∫ x : Ω in Set.univ, exp (t * X x) ∂μ := by
  simp only [Measure.restrict_univ]

Result:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
⊢ 0 < ∫ (x : Ω), rexp (t * X x) ∂μ

Proof state:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
⊢ IntegrableOn (fun x => rexp (t * X x)) Set.univ μ

Tactic:
rwa [integrableOn_univ]

Result:
no goals

Proof state:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
h_eq_univ : (Function.support fun x => rexp (t * X x)) = Set.univ
⊢ μ Set.univ ≠ ⊥

Tactic:
simp only [hμ, ENNReal.bot_eq_zero, Ne, Measure.measure_univ_eq_zero, not_false_iff]

Result:
no goals

Proof state:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
⊢ 0 ≤ᶠ[ae (μ.restrict Set.univ)] fun x => rexp (t * X x)

Tactic:
filter_upwards with x

Result:
case h
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
x : Ω
⊢ 0 x ≤ rexp (t * X x)

Proof state:
case h
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
x : Ω
⊢ 0 ≤ rexp (t * X x)

Tactic:
exact (exp_pos _).le

Result:
no goals

Proof state:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
h_eq_univ : (Function.support fun x => rexp (t * X x)) = Set.univ
⊢ 0 < μ Set.univ

Tactic:
refine Ne.bot_lt ?_

Result:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
h_eq_univ : (Function.support fun x => rexp (t * X x)) = Set.univ
⊢ μ Set.univ ≠ ⊥

Proof state:
case h
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
x : Ω
⊢ 0 x ≤ rexp (t * X x)

Tactic:
rw [Pi.zero_apply]

Result:
case h
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
x : Ω
⊢ 0 ≤ rexp (t * X x)

Proof state:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
⊢ 0 < μ ((Function.support fun x => rexp (t * X x)) ∩ Set.univ)

Tactic:
have h_eq_univ : (Function.support fun x : Ω => exp (t * X x)) = Set.univ := by
  ext1 x
  simp only [Function.mem_support, Set.mem_univ, iff_true]
  exact (exp_pos _).ne'

Result:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
h_eq_univ : (Function.support fun x => rexp (t * X x)) = Set.univ
⊢ 0 < μ ((Function.support fun x => rexp (t * X x)) ∩ Set.univ)

Proof state:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
⊢ 0 < ∫ (x : Ω), rexp (t * X x) ∂μ

Tactic:
rw [this, setIntegral_pos_iff_support_of_nonneg_ae _ _]

Result:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
⊢ 0 < μ ((Function.support fun x => rexp (t * X x)) ∩ Set.univ)

Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
⊢ 0 ≤ᶠ[ae (μ.restrict Set.univ)] fun x => rexp (t * X x)

Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
⊢ IntegrableOn (fun x => rexp (t * X x)) Set.univ μ

Proof state:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
⊢ 0 < mgf X μ t

Tactic:
simp_rw [mgf]

Result:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
⊢ 0 < ∫ (x : Ω), rexp (t * X x) ∂μ

Proof state:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
⊢ (Function.support fun x => rexp (t * X x)) = Set.univ

Tactic:
ext1 x

Result:
case h
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
x : Ω
⊢ (x ∈ Function.support fun x => rexp (t * X x)) ↔ x ∈ Set.univ

Proof state:
case h
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
this : ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ
x : Ω
⊢ rexp (t * X x) ≠ 0

Tactic:
exact (exp_pos _).ne'

Result:
no goals

Proof state:
Ω : Type u_1
m : MeasurableSpace Ω
X : Ω → ℝ
μ : Measure Ω
t : ℝ
hμ : μ ≠ 0
h_int_X : Integrable (fun ω => rexp (t * X ω)) μ
⊢ ∫ (x : Ω), rexp (t * X x) ∂μ = ∫ (x : Ω) in Set.univ, rexp (t * X x) ∂μ

Tactic:
simp only [Measure.restrict_univ]

Result:
no goals