{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2013:LBQO57VFYN7DI25Z5IQ7PROFKI","short_pith_number":"pith:LBQO57VF","canonical_record":{"source":{"id":"1308.5998","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.NA","submitted_at":"2013-08-27T21:14:04Z","cross_cats_sorted":[],"title_canon_sha256":"0f4f517bec96cd4de7124ac9fc2db20cb73ea0e5f35e484d11779001b9c36e26","abstract_canon_sha256":"dc064e49b04ef39b4a489c8f39fd08eb48778d4889d7a9fe493eb79db6bb7d8d"},"schema_version":"1.0"},"canonical_sha256":"5860eefea5c37e346bb9ea21f7c5c552259cf561d0038652f8e332ea6c64ad12","source":{"kind":"arxiv","id":"1308.5998","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1308.5998","created_at":"2026-05-18T03:14:49Z"},{"alias_kind":"arxiv_version","alias_value":"1308.5998v1","created_at":"2026-05-18T03:14:49Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1308.5998","created_at":"2026-05-18T03:14:49Z"},{"alias_kind":"pith_short_12","alias_value":"LBQO57VFYN7D","created_at":"2026-05-18T12:27:51Z"},{"alias_kind":"pith_short_16","alias_value":"LBQO57VFYN7DI25Z","created_at":"2026-05-18T12:27:51Z"},{"alias_kind":"pith_short_8","alias_value":"LBQO57VF","created_at":"2026-05-18T12:27:51Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2013:LBQO57VFYN7DI25Z5IQ7PROFKI","target":"record","payload":{"canonical_record":{"source":{"id":"1308.5998","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.NA","submitted_at":"2013-08-27T21:14:04Z","cross_cats_sorted":[],"title_canon_sha256":"0f4f517bec96cd4de7124ac9fc2db20cb73ea0e5f35e484d11779001b9c36e26","abstract_canon_sha256":"dc064e49b04ef39b4a489c8f39fd08eb48778d4889d7a9fe493eb79db6bb7d8d"},"schema_version":"1.0"},"canonical_sha256":"5860eefea5c37e346bb9ea21f7c5c552259cf561d0038652f8e332ea6c64ad12","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T03:14:49.366636Z","signature_b64":"gyBzoH9GZUDVE+12b80b6GXkU+1HxojB5jtAMp6TM8UrKC3ilNGTWqJI0AZktABh24Q7tFWmeqnJoQ1DzcOyBA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"5860eefea5c37e346bb9ea21f7c5c552259cf561d0038652f8e332ea6c64ad12","last_reissued_at":"2026-05-18T03:14:49.366054Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T03:14:49.366054Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1308.5998","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T03:14:49Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"Vl367raHulo9v1dxXO8OFwKu9NtfahLWoey3q2ddhQlGX7ys8beET6MuhSEdNGIiBNbzWRntKeLKNZlvz+i3CQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-22T11:31:54.890948Z"},"content_sha256":"10f17645bef9ac2e7101af6e0116e4fc392ad869b298966f3160dc8900720877","schema_version":"1.0","event_id":"sha256:10f17645bef9ac2e7101af6e0116e4fc392ad869b298966f3160dc8900720877"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2013:LBQO57VFYN7DI25Z5IQ7PROFKI","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"A spectrally accurate direct solution technique for frequency-domain scattering problems with variable media","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"math.NA","authors_text":"Adrianna Gillman, Alex Barnett, Per-Gunnar Martinsson","submitted_at":"2013-08-27T21:14:04Z","abstract_excerpt":"This paper presents a direct solution technique for the scattering of time-harmonic waves from a bounded region of the plane in which the wavenumber varies smoothly in space.The method constructs the interior Dirichlet-to-Neumann (DtN) map for the bounded region via bottom-up recursive merges of (discretization of) certain boundary operators on a quadtree of boxes.These operators take the form of impedance-to-impedance (ItI) maps. Since ItI maps are unitary, this formulation is inherently numerically stable, and is immune to problems of artificial internal resonances. The ItI maps on the small"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1308.5998","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":""},"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"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T03:14:49Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"b0wYEqHRIvXwH6ngoOpmlIUg9XpfqwMYBJYPlDS72pccNwiaSFpsPSKuvHxoybRYSUDQI2r0meBnUAn6bwDqDw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-22T11:31:54.891590Z"},"content_sha256":"1690acbcc0270da1c1618ef3f803532765b80ae89d21ef0d24792088a60d502d","schema_version":"1.0","event_id":"sha256:1690acbcc0270da1c1618ef3f803532765b80ae89d21ef0d24792088a60d502d"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/LBQO57VFYN7DI25Z5IQ7PROFKI/bundle.json","state_url":"https://pith.science/pith/LBQO57VFYN7DI25Z5IQ7PROFKI/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/LBQO57VFYN7DI25Z5IQ7PROFKI/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-05-22T11:31:54Z","links":{"resolver":"https://pith.science/pith/LBQO57VFYN7DI25Z5IQ7PROFKI","bundle":"https://pith.science/pith/LBQO57VFYN7DI25Z5IQ7PROFKI/bundle.json","state":"https://pith.science/pith/LBQO57VFYN7DI25Z5IQ7PROFKI/state.json","well_known_bundle":"https://pith.science/.well-known/pith/LBQO57VFYN7DI25Z5IQ7PROFKI/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2013:LBQO57VFYN7DI25Z5IQ7PROFKI","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"dc064e49b04ef39b4a489c8f39fd08eb48778d4889d7a9fe493eb79db6bb7d8d","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.NA","submitted_at":"2013-08-27T21:14:04Z","title_canon_sha256":"0f4f517bec96cd4de7124ac9fc2db20cb73ea0e5f35e484d11779001b9c36e26"},"schema_version":"1.0","source":{"id":"1308.5998","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1308.5998","created_at":"2026-05-18T03:14:49Z"},{"alias_kind":"arxiv_version","alias_value":"1308.5998v1","created_at":"2026-05-18T03:14:49Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1308.5998","created_at":"2026-05-18T03:14:49Z"},{"alias_kind":"pith_short_12","alias_value":"LBQO57VFYN7D","created_at":"2026-05-18T12:27:51Z"},{"alias_kind":"pith_short_16","alias_value":"LBQO57VFYN7DI25Z","created_at":"2026-05-18T12:27:51Z"},{"alias_kind":"pith_short_8","alias_value":"LBQO57VF","created_at":"2026-05-18T12:27:51Z"}],"graph_snapshots":[{"event_id":"sha256:1690acbcc0270da1c1618ef3f803532765b80ae89d21ef0d24792088a60d502d","target":"graph","created_at":"2026-05-18T03:14:49Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"This paper presents a direct solution technique for the scattering of time-harmonic waves from a bounded region of the plane in which the wavenumber varies smoothly in space.The method constructs the interior Dirichlet-to-Neumann (DtN) map for the bounded region via bottom-up recursive merges of (discretization of) certain boundary operators on a quadtree of boxes.These operators take the form of impedance-to-impedance (ItI) maps. Since ItI maps are unitary, this formulation is inherently numerically stable, and is immune to problems of artificial internal resonances. The ItI maps on the small","authors_text":"Adrianna Gillman, Alex Barnett, Per-Gunnar Martinsson","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.NA","submitted_at":"2013-08-27T21:14:04Z","title":"A spectrally accurate direct solution technique for frequency-domain scattering problems with variable media"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1308.5998","kind":"arxiv","version":1},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:10f17645bef9ac2e7101af6e0116e4fc392ad869b298966f3160dc8900720877","target":"record","created_at":"2026-05-18T03:14:49Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"dc064e49b04ef39b4a489c8f39fd08eb48778d4889d7a9fe493eb79db6bb7d8d","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.NA","submitted_at":"2013-08-27T21:14:04Z","title_canon_sha256":"0f4f517bec96cd4de7124ac9fc2db20cb73ea0e5f35e484d11779001b9c36e26"},"schema_version":"1.0","source":{"id":"1308.5998","kind":"arxiv","version":1}},"canonical_sha256":"5860eefea5c37e346bb9ea21f7c5c552259cf561d0038652f8e332ea6c64ad12","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"5860eefea5c37e346bb9ea21f7c5c552259cf561d0038652f8e332ea6c64ad12","first_computed_at":"2026-05-18T03:14:49.366054Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T03:14:49.366054Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"gyBzoH9GZUDVE+12b80b6GXkU+1HxojB5jtAMp6TM8UrKC3ilNGTWqJI0AZktABh24Q7tFWmeqnJoQ1DzcOyBA==","signature_status":"signed_v1","signed_at":"2026-05-18T03:14:49.366636Z","signed_message":"canonical_sha256_bytes"},"source_id":"1308.5998","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:10f17645bef9ac2e7101af6e0116e4fc392ad869b298966f3160dc8900720877","sha256:1690acbcc0270da1c1618ef3f803532765b80ae89d21ef0d24792088a60d502d"],"state_sha256":"6e982f21758e9a2bb58e6683c25523eadeec77d8f2826ae96f85ddb4e3b3a326"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"cyI0sYb/mbTb+Eu1SGo7DhTtTx2tORTkIcLeitX6wIXhRfEPLWnCyRT4Tmcqo99tWupI7Lh+0428YT9BZ0WWCg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-22T11:31:54.896551Z","bundle_sha256":"9cd0b97b34649c17a3accf63c1c174104863533836b4140c1dde3cc04abd4b54"}}