Prove2Me
Navigate
DiscoverCollectionsFormalpediaBlogsUsersMomentumMy Missions+
Prove2Me
⌕
Log in
← Formalpedia

§3.2, p. 13 — low-type incentive condition iff θH/θL ≥ ΔL

Proved
CustomerVoice.ALearn.icl_iff_threshold

by mikedeng1 · Oct 15, 2026 · Mathlib 0df444a (Lean v4.33.1)

cheap-talkincentive-compatibilityp2o-batch-pfp2ap2o-gran-per-chapterp2o-plan-paperp2o-v1threshold

Under the A-Learning model's standing assumptions, the low-type buyer weakly prefers truthful communication to overstating its preference if and only if

θHθL≥ΔL=2s+γkγk.\frac{\theta_H}{\theta_L}\geq\Delta_L=\frac{2s+\gamma k}{\gamma k}.θL​θH​​≥ΔL​=γk2s+γk​.

The buyer payoff allows the low type to decline a product priced above its valuation.

This gives the low-type component of the threshold in Proposition 1.

Formalization Note The weak inequality is the statement on p. 13 and in Proposition 1. The max with zero in the payoff is essential for the low type's deviation; the pricing stage enters through equation (5).

Preamble
import Mathlib
import Definitions.Def_CustomerVoice_ALearn_Setting
Formal statement
namespace CustomerVoice.ALearn

/-- §3.2, p. 13: the low-type IC condition is the threshold condition. -/
theorem icl_iff_threshold (M : Model) (hM : M.Standing) :
    M.ICL ↔ M.θH / M.θL ≥ M.DeltaL := by sorry

end CustomerVoice.ALearn
Source
Guo, The Voice of Customers in Customization, SSRN working paper 3994319 (version of 2023-11-29, https://ssrn.com/abstract=3994319), p. 13, §3.2, low-type threshold sentence following Proposition 1
Human review
  • Endorsed by Shuze Chen · Oct 16, 2026

    Confirmed by the moderator at approval.

  • Endorsed by mikedeng1 · Oct 16, 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