{"paper":{"title":"A Stable SBP-SAT FDTD Subgridding Method Without Region Split","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Projection SBP operators enable stable FDTD subgridding with direct coarse-fine coupling and no domain split.","cross_cats":[],"primary_cat":"cs.CE","authors_text":"Hanhong Liu, Jian Wang, Langran Deng, Shunchuan Yang, Weibo Wu, Wei-Jie Wang, Xingqi Zhang, Xinyue Zhang, Yuhui Wang, Zhizhang Chen","submitted_at":"2026-04-16T04:57:27Z","abstract_excerpt":"A provably stable summation-by-parts simultaneous approximation term (SBP-SAT) finite-difference time-domain (FDTD) subgridding method without region split is proposed. By designing projection SBP operators tailored for embedded topological features and deriving the corresponding SAT boundary conditions, this approach guarantees long-time stability through discrete energy analysis. Unlike conventional SBP-SAT FDTD subgridding techniques that rely on aligned or multi-block configurations, the proposed method enables a direct coupling between an internal refined region and a single surrounding c"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"By designing projection SBP operators tailored for embedded topological features and deriving the corresponding SAT boundary conditions, this approach guarantees long-time stability through discrete energy analysis.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That projection SBP operators can be constructed for arbitrary embedded topological features while preserving the summation-by-parts property and enabling stable SAT coupling without additional assumptions on grid alignment or topology.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"A provably stable SBP-SAT FDTD subgridding method is proposed that enables direct coupling of an embedded refined region to a single surrounding coarse-grid domain without region splitting or auxiliary blocks.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Projection SBP operators enable stable FDTD subgridding with direct coarse-fine coupling and no domain split.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"4aeaa0ac5256046e8d7dff38d2124fac74e23e5e20d04e9d3b11b14aa934570e"},"source":{"id":"2604.14618","kind":"arxiv","version":2},"verdict":{"id":"3c03f7f4-ffe6-4c61-a02a-ad1da089d00e","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-10T09:32:14.087996Z","strongest_claim":"By designing projection SBP operators tailored for embedded topological features and deriving the corresponding SAT boundary conditions, this approach guarantees long-time stability through discrete energy analysis.","one_line_summary":"A provably stable SBP-SAT FDTD subgridding method is proposed that enables direct coupling of an embedded refined region to a single surrounding coarse-grid domain without region splitting or auxiliary blocks.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That projection SBP operators can be constructed for arbitrary embedded topological features while preserving the summation-by-parts property and enabling stable SAT coupling without additional assumptions on grid alignment or topology.","pith_extraction_headline":"Projection SBP operators enable stable FDTD subgridding with direct coarse-fine coupling and no domain split."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.14618/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"}