{"id":"891d2bcc-3cfe-4ed6-8a3d-24fd28bbcfb9","arxiv_id":"1908.00386","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":0,"one_line_summary":"All boundaries of the m=2 amplituhedron A_{n,k}^{(2)} are classified, the boundary poset is Eulerian, and the Euler characteristic equals one.","lead":"This paper classifies all boundary faces of m=2 amplituhedra, geometric objects that generalize polytopes and carry information about scattering amplitudes in a supersymmetric quantum theory. It introduces a diagrammatic notation and reports that the boundary structure satisfies the Euler characteristic condition needed for the space to be a ball.","discovery_kind":"new_application","skeptic_critique":null,"referee_report":null,"author_rebuttal":null,"desk_editor":null,"rs_alignment":null,"lean_confirmation":null,"pith_extraction":null,"created_at":"2026-08-14T15:59:11.131780+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":null,"supporting_citations":[],"review_version":1}