A zero guarantee with a minus-200 outcome: penaltyblog partial hedging

Abstract

A reproducible payoff inconsistency in penaltyblog arbitrage_hedge(hedge_all=False), source-pinned to 72de6519e0c9a357b8b1aa2a6441a454b18ff54e (project metadata 1.13.0). In a synthetic two-outcome case the function reports guaranteed profit 0 while its returned back positions have net payoffs +300 and -200. Five selected nonzero partial-mode cases violate the exact cash-ledger invariant; zero-exposure and full-hedge controls pass. Contains an unchanged MIT-licensed upstream module, verification script, machine-readable replay and detailed report. No complete patch, maintainer acceptance, real bets, customer losses, external peer review or worldwide priority claimed. AI-assisted investigation and writing. Original report CC BY 4.0; original replay code MIT; upstream licence retained. Authors: Xamit Kadirbekov and Daniyal Kadirbekov / GERO. Report: https://www.gero.uz/research/articles/penaltyblog-partial-hedge-payoff.htmlDeveloper report: https://github.com/martineastwood/penaltyblog/issues/50