The next killed record dominates the countable measurable shifted two-sided exit reward
ProvedAvramDividend.Classical.killed_nextRecord_weight_ge_countable_twoSided_rewardFor a realised surviving record b at a finite time u, its discounted next-record payment dominates the prior discount times the explicitly countable future two-sided exit reward. This combines the proved actual killed-record pathwise domination with the proved shifted Lévy schedule identity, placing the payoff directly in the measurable form required by the stopped strong-Markov step.
Preamble
import Mathlib.Data.ENNReal.Basic import Mathlib.Data.Nat.Pairing import Mathlib.Analysis.Complex.Exponential import Definitions.Def_AvramDividend_Classical_TwoSidedExit import Theorems.Thm_AvramDividend_Classical_killed_nextRecord_weight_ge_shifted_twoSided_reward import Theorems.Thm_AvramDividend_Classical_levy_shifted_trueTwoSided_reward_eq_schedule open MeasureTheory Set open scoped NNReal ENNReal open AvramDividend.Classical
Formal statement
theorem AvramDividend.Classical.killed_nextRecord_weight_ge_countable_twoSided_reward
{Ω : Type*} [mΩ : MeasurableSpace Ω] {P : Measure Ω}
{𝓕 : Filtration ℝ≥0 mΩ}
(X : SpectrallyNegativeLevy P 𝓕)
(a b ε q : ℝ) (ha : 0 < a) (hb : 0 ≤ b) (hε : 0 ≤ ε)
(ω : Ω) (u : ℝ≥0)
(hu : (u : ℝ≥0∞) = twoSidedExitUpTime X b ω)
(hAt : X.X u ω = b)
(hBefore : (u : ℝ≥0∞) < barrierRuinTime X a ω) :
ENNReal.ofReal ε *
(ENNReal.ofReal (Real.exp (-(q * (u : ℝ)))) *
(let g : ℝ≥0 → ℝ := fun t => X.X (u + t) ω - X.X u ω
let τ : ℕ → ℝ≥0 := fun j =>
((Nat.unpair j).2 : ℝ≥0) *
(((((Nat.unpair j).1 + 1) : ℕ) : ℝ≥0)⁻¹)
let ρ : ℝ≥0∞ := ⨅ j : ℕ,
if ε < g (τ j) then (τ j : ℝ≥0∞) else ⊤
let σ : ℝ≥0∞ := ⨅ j : ℕ,
if g (τ j) < ε - a then (τ j : ℝ≥0∞) else ⊤
if ρ < σ then
ENNReal.ofReal (Real.exp (-(q * ρ.toReal)))
else 0)) ≤
(if twoSidedExitUpTime X (b + ε) ω < barrierRuinTime X a ω then
ENNReal.ofReal (ε * Real.exp
(-(q * (twoSidedExitUpTime X (b + ε) ω).toReal)))
else 0) := by sorrySource
Composition of the Proved killed_nextRecord_weight_ge_shifted_twoSided_reward and levy_shifted_trueTwoSided_reward_eq_schedule.