{"paper":{"title":"Scalaron-modified null focusing and radial monotonicity in static f(R) gravity","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"gr-qc","authors_text":"Francisco S. N. Lobo, Francisco Tello-Ortiz, Jean B\\'aez Cuevas, Maickol Mu\\~noz-Palma","submitted_at":"2026-08-09T17:08:54Z","abstract_excerpt":"We derive an exact radial monotonicity law for static, spherically symmetric spacetimes in metric \\(f(R)\\) gravity. For \\(ds^2=A(r)dt^2-dr^2/B(r)-r^2d\\Omega^2\\), the matter contribution and the scalaron Hessian combine into an effective radial-convergence numerator that fixes the derivative of \\(\\Q=B/A\\). On every connected static interval with \\(A>0\\), \\(B>0\\), and \\(f_R\\equiv df/dR>0\\), its sign therefore determines the monotonicity of \\(\\Q\\). The integrated identity retains the finite, generally nonzero value of \\(B/A\\) at a regular nondegenerate Killing horizon; consequently, a fixed-sign "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2608.08818","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2608.08818/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}