{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2014:NJNO2QSDUGEQTB4MTEFAO4IESJ","short_pith_number":"pith:NJNO2QSD","schema_version":"1.0","canonical_sha256":"6a5aed4243a18909878c990a07710492400aa883048caa473d4cbe7425b23d6c","source":{"kind":"arxiv","id":"1401.2115","version":6},"attestation_state":"computed","paper":{"title":"Mathematical Properties of a Class of Four-dimensional Neutral Signature Metrics","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"math.DG","authors_text":"A. Coley, D. Brooks, D. McNutt, N. Musoke","submitted_at":"2014-01-09T18:55:42Z","abstract_excerpt":"While the Lorenzian and Riemanian metrics for which all polynomial scalar curvature invariants vanish (the VSI property) are well-studied, less is known about the four-dimensional neutral signature metrics with the VSI property. Recently it was shown that the neutral signature metrics belong to two distinct subclasses: the Walker and Kundt metrics. In this paper we have chosen an example from each of the two subcases of the Ricci-flat VSI Walker metrics respectively.\n  To investigate the difference between the metrics we determine the existence of a null, geodesic, expansion-free, shear-free a"},"verification_status":{"content_addressed":true,"pith_receipt":true,"author_attested":false,"weak_author_claims":0,"strong_author_claims":0,"externally_anchored":false,"storage_verified":false,"citation_signatures":0,"replication_records":0,"graph_snapshot":true,"references_resolved":false,"formal_links_present":false},"canonical_record":{"source":{"id":"1401.2115","kind":"arxiv","version":6},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.DG","submitted_at":"2014-01-09T18:55:42Z","cross_cats_sorted":[],"title_canon_sha256":"2a404f9a976c47ae3e565e9c347f53dbebc410fb3aa5d8881dc699c5efcd7d1b","abstract_canon_sha256":"9170a0956a5b4f6a9445ed909c0039e5e309711b5b95c64bc3f0b53d875d1e85"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:25:08.771082Z","signature_b64":"66UnqKJ0KhSof6W7JmWLuF0EWNBn5xlQvHAdmUl5Pv+p9k7zN9eeZPGlfAsprX98mm+1UVM3pwM0K8dRpGjjBg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"6a5aed4243a18909878c990a07710492400aa883048caa473d4cbe7425b23d6c","last_reissued_at":"2026-05-18T01:25:08.770485Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:25:08.770485Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"Mathematical Properties of a Class of Four-dimensional Neutral Signature Metrics","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"math.DG","authors_text":"A. Coley, D. Brooks, D. McNutt, N. Musoke","submitted_at":"2014-01-09T18:55:42Z","abstract_excerpt":"While the Lorenzian and Riemanian metrics for which all polynomial scalar curvature invariants vanish (the VSI property) are well-studied, less is known about the four-dimensional neutral signature metrics with the VSI property. Recently it was shown that the neutral signature metrics belong to two distinct subclasses: the Walker and Kundt metrics. In this paper we have chosen an example from each of the two subcases of the Ricci-flat VSI Walker metrics respectively.\n  To investigate the difference between the metrics we determine the existence of a null, geodesic, expansion-free, shear-free a"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1401.2115","kind":"arxiv","version":6},"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"},"aliases":[{"alias_kind":"arxiv","alias_value":"1401.2115","created_at":"2026-05-18T01:25:08.770617+00:00"},{"alias_kind":"arxiv_version","alias_value":"1401.2115v6","created_at":"2026-05-18T01:25:08.770617+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1401.2115","created_at":"2026-05-18T01:25:08.770617+00:00"},{"alias_kind":"pith_short_12","alias_value":"NJNO2QSDUGEQ","created_at":"2026-05-18T12:28:41.024544+00:00"},{"alias_kind":"pith_short_16","alias_value":"NJNO2QSDUGEQTB4M","created_at":"2026-05-18T12:28:41.024544+00:00"},{"alias_kind":"pith_short_8","alias_value":"NJNO2QSD","created_at":"2026-05-18T12:28:41.024544+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":0,"internal_anchor_count":0,"sample":[]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/NJNO2QSDUGEQTB4MTEFAO4IESJ","json":"https://pith.science/pith/NJNO2QSDUGEQTB4MTEFAO4IESJ.json","graph_json":"https://pith.science/api/pith-number/NJNO2QSDUGEQTB4MTEFAO4IESJ/graph.json","events_json":"https://pith.science/api/pith-number/NJNO2QSDUGEQTB4MTEFAO4IESJ/events.json","paper":"https://pith.science/paper/NJNO2QSD"},"agent_actions":{"view_html":"https://pith.science/pith/NJNO2QSDUGEQTB4MTEFAO4IESJ","download_json":"https://pith.science/pith/NJNO2QSDUGEQTB4MTEFAO4IESJ.json","view_paper":"https://pith.science/paper/NJNO2QSD","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=1401.2115&json=true","fetch_graph":"https://pith.science/api/pith-number/NJNO2QSDUGEQTB4MTEFAO4IESJ/graph.json","fetch_events":"https://pith.science/api/pith-number/NJNO2QSDUGEQTB4MTEFAO4IESJ/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/NJNO2QSDUGEQTB4MTEFAO4IESJ/action/timestamp_anchor","attest_storage":"https://pith.science/pith/NJNO2QSDUGEQTB4MTEFAO4IESJ/action/storage_attestation","attest_author":"https://pith.science/pith/NJNO2QSDUGEQTB4MTEFAO4IESJ/action/author_attestation","sign_citation":"https://pith.science/pith/NJNO2QSDUGEQTB4MTEFAO4IESJ/action/citation_signature","submit_replication":"https://pith.science/pith/NJNO2QSDUGEQTB4MTEFAO4IESJ/action/replication_record"}},"created_at":"2026-05-18T01:25:08.770617+00:00","updated_at":"2026-05-18T01:25:08.770617+00:00"}