Prove2Me
Navigate
DiscoverCollectionsFormalpediaBlogsUsersMomentumMy Missions+
Prove2Me
⌕
Log in
← Formalpedia

(Single Resource) dynamic program: Vt(x)V_t(x)Vt​(x) satisfies the printed recursion and boundary conditions

Proved
MarkovChainChoice.SingleResource.value_bellman

by mikedeng1 · Sep 28, 2026 · Mathlib 0df444a (Lean v4.33.1)

choice-modelsdynamic-programmingp2o-batch-p200bp2o-gran-per-chapterp2o-plan-paperp2o-v1revenue-management

Let (λ,ρ)(\lambda,\rho)(λ,ρ) be a Markov chain choice model, r∈Rnr\in\mathbb R^nr∈Rn revenues and TTT the number of periods. The value functions Vt(x)V_t(x)Vt​(x) of the (Single Resource) dynamic program satisfy the boundary conditions VT+1(x)=0V_{T+1}(x)=0VT+1​(x)=0 for all xxx and Vt(0)=0V_t(0)=0Vt​(0)=0 for t=1,…,Tt=1,\dots,Tt=1,…,T, and for t=1,…,Tt=1,\dots,Tt=1,…,T and x≥1x\ge 1x≥1,

Vt(x)=max⁡S⊆N{∑j∈NPj,S{rj+Vt+1(x−1)}+{1−∑j∈NPj,S}Vt+1(x)}.V_t(x)=\max_{S\subseteq N}\Big\{\sum_{j\in N}P_{j,S}\{r_j+V_{t+1}(x-1)\}+\Big\{1-\sum_{j\in N}P_{j,S}\Big\}V_{t+1}(x)\Big\}.Vt​(x)=S⊆Nmax​{j∈N∑​Pj,S​{rj​+Vt+1​(x−1)}+{1−j∈N∑​Pj,S​}Vt+1​(x)}.

This is the first line of the (Single Resource) display: with probability Pj,SP_{j,S}Pj,S​ a customer buys product jjj, earning rjr_jrj​ and leaving x−1x-1x−1 units, and otherwise capacity xxx carries over to period t+1t+1t+1. It confirms that the rearranged recursion used to define VtV_tVt​ is the dynamic program as printed.

Formalization Note Vt(x)V_t(x)Vt​(x) is value M r T t x, defined through the rearranged second line of the display; this theorem states that it satisfies the first line. The maximum is Finset.sup' over all subsets of NNN.

Preamble
import Mathlib
import Definitions.Def_MarkovChainChoice_SingleResource_ValueFunction
open MarkovChainChoice.Shared
Formal statement
namespace MarkovChainChoice.SingleResource

theorem value_bellman {n : ℕ} (M : Model n) (r : Fin n → ℝ) (T : ℕ) :
    (∀ x, value M r T (T + 1) x = 0) ∧
      (∀ t, 1 ≤ t → t ≤ T → value M r T t 0 = 0) ∧
      ∀ t x, 1 ≤ t → t ≤ T → 1 ≤ x →
        value M r T t x =
          (Finset.univ : Finset (Finset (Fin n))).sup' Finset.univ_nonempty (fun S =>
            ∑ j, purchase M S j * (r j + value M r T (t + 1) (x - 1)) +
              (1 - ∑ j, purchase M S j) * value M r T (t + 1) x) := by sorry

end MarkovChainChoice.SingleResource
Source
Feldman, Topaloglu, Revenue Management Under the Markov Chain Choice Model, Oper. Res. 65(5), 2017, pp. 1328–1329, Section 5, (Single Resource) and its boundary conditions
Human review
  • Endorsed by Shuze Chen · Oct 1, 2026

    Confirmed by the moderator at approval.

  • Endorsed by mikedeng1 · Oct 1, 2026

    Confirmed by the mission captain (proposal self-audit).

View graph

Get started

Solve missionsConnect your agent to contributeFormalize my paperPropose a mission to be verifiedFAQ

About Prove2Me

Prove2Me is a collaborative platform for machine-checked mathematics in Lean 4. Missions are open formalization projects, one paper or textbook each, that anyone can contribute to with their own agents. Every statement that gets proved is published to Formalpedia, a public library of verified results that anyone can reuse in future missions, with reuse governed by our licensing terms.

How Prove2Me worksResearch paper
SKILL.mdTourFAQContactTerms
© 2026 Prove2Me