{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2013:XUT2HSPOQONLH7VAMTHHDPJDTQ","short_pith_number":"pith:XUT2HSPO","canonical_record":{"source":{"id":"1306.0149","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math-ph","submitted_at":"2013-06-01T20:57:47Z","cross_cats_sorted":["gr-qc","math.AP","math.MP"],"title_canon_sha256":"b578a433262d1cd49376e060b20c4f6611fb608fd8e85d4a57f1d7836a796bcf","abstract_canon_sha256":"8533bc97a16b56493832909ff3471493d97cb3b63182bbbf1245729a27179e1a"},"schema_version":"1.0"},"canonical_sha256":"bd27a3c9ee839ab3fea064ce71bd239c16ea896f1c6db6e41c934bbd19d95922","source":{"kind":"arxiv","id":"1306.0149","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1306.0149","created_at":"2026-05-18T01:49:38Z"},{"alias_kind":"arxiv_version","alias_value":"1306.0149v2","created_at":"2026-05-18T01:49:38Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1306.0149","created_at":"2026-05-18T01:49:38Z"},{"alias_kind":"pith_short_12","alias_value":"XUT2HSPOQONL","created_at":"2026-05-18T12:28:06Z"},{"alias_kind":"pith_short_16","alias_value":"XUT2HSPOQONLH7VA","created_at":"2026-05-18T12:28:06Z"},{"alias_kind":"pith_short_8","alias_value":"XUT2HSPO","created_at":"2026-05-18T12:28:06Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2013:XUT2HSPOQONLH7VAMTHHDPJDTQ","target":"record","payload":{"canonical_record":{"source":{"id":"1306.0149","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math-ph","submitted_at":"2013-06-01T20:57:47Z","cross_cats_sorted":["gr-qc","math.AP","math.MP"],"title_canon_sha256":"b578a433262d1cd49376e060b20c4f6611fb608fd8e85d4a57f1d7836a796bcf","abstract_canon_sha256":"8533bc97a16b56493832909ff3471493d97cb3b63182bbbf1245729a27179e1a"},"schema_version":"1.0"},"canonical_sha256":"bd27a3c9ee839ab3fea064ce71bd239c16ea896f1c6db6e41c934bbd19d95922","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:49:38.859147Z","signature_b64":"IhR1od0rzCI9jMK5EIoP0r8KXGJQf4HIhoxrmIbA+Wt/KtZ9+Cr8ynxSd5UZeVr6yy88dF32nhvCNkw20VM/Cg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"bd27a3c9ee839ab3fea064ce71bd239c16ea896f1c6db6e41c934bbd19d95922","last_reissued_at":"2026-05-18T01:49:38.857822Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:49:38.857822Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1306.0149","source_version":2,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T01:49:38Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"9l2XypXBLfswZEoy9VZl+1fHFTIWoi0IkR+srA/ATOL7cnQZtW3zuspLj+L70PiBbQVZMKHzdeuHnfgiQANGDg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-20T13:38:27.540736Z"},"content_sha256":"5d5121e98ebab4c503142b0d87c6b38c9c2a8703e59185407274dcc01df1e50a","schema_version":"1.0","event_id":"sha256:5d5121e98ebab4c503142b0d87c6b38c9c2a8703e59185407274dcc01df1e50a"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2013:XUT2HSPOQONLH7VAMTHHDPJDTQ","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Nonstationary analogue black holes","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["gr-qc","math.AP","math.MP"],"primary_cat":"math-ph","authors_text":"Gregory Eskin","submitted_at":"2013-06-01T20:57:47Z","abstract_excerpt":"We study the existence of analogue nonstationary spherically symmetric black holes. The prime example is the acoustic model (cf. [V], [U]). We consider also a more general class of metrics that could be useful in other physical models of analogue black and white holes.\n  We give examples of the appearance of black holes and of disappearance of white holes. We also discuss the relation between the apparent and the event horizons for the case of analogue black holes. In the end we study the inverse problem of determination of black or white holes by boundary measurements for the spherically symm"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1306.0149","kind":"arxiv","version":2},"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":"2026-05-18T01:49:38Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"85TkS309YzYmAqYTbwyXVImhr5q0t/1XoLXFctR1gbnvD7TTVhUfO9teoszgL5ybKWiX5P3C5+K/eUMWaUn9DA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-20T13:38:27.541102Z"},"content_sha256":"0b8990c7bc2140100a73aa237faec002e67d89fea59f24151997bb5e61233fa0","schema_version":"1.0","event_id":"sha256:0b8990c7bc2140100a73aa237faec002e67d89fea59f24151997bb5e61233fa0"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/XUT2HSPOQONLH7VAMTHHDPJDTQ/bundle.json","state_url":"https://pith.science/pith/XUT2HSPOQONLH7VAMTHHDPJDTQ/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/XUT2HSPOQONLH7VAMTHHDPJDTQ/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":"2026-06-20T13:38:27Z","links":{"resolver":"https://pith.science/pith/XUT2HSPOQONLH7VAMTHHDPJDTQ","bundle":"https://pith.science/pith/XUT2HSPOQONLH7VAMTHHDPJDTQ/bundle.json","state":"https://pith.science/pith/XUT2HSPOQONLH7VAMTHHDPJDTQ/state.json","well_known_bundle":"https://pith.science/.well-known/pith/XUT2HSPOQONLH7VAMTHHDPJDTQ/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2013:XUT2HSPOQONLH7VAMTHHDPJDTQ","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":"8533bc97a16b56493832909ff3471493d97cb3b63182bbbf1245729a27179e1a","cross_cats_sorted":["gr-qc","math.AP","math.MP"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math-ph","submitted_at":"2013-06-01T20:57:47Z","title_canon_sha256":"b578a433262d1cd49376e060b20c4f6611fb608fd8e85d4a57f1d7836a796bcf"},"schema_version":"1.0","source":{"id":"1306.0149","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1306.0149","created_at":"2026-05-18T01:49:38Z"},{"alias_kind":"arxiv_version","alias_value":"1306.0149v2","created_at":"2026-05-18T01:49:38Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1306.0149","created_at":"2026-05-18T01:49:38Z"},{"alias_kind":"pith_short_12","alias_value":"XUT2HSPOQONL","created_at":"2026-05-18T12:28:06Z"},{"alias_kind":"pith_short_16","alias_value":"XUT2HSPOQONLH7VA","created_at":"2026-05-18T12:28:06Z"},{"alias_kind":"pith_short_8","alias_value":"XUT2HSPO","created_at":"2026-05-18T12:28:06Z"}],"graph_snapshots":[{"event_id":"sha256:0b8990c7bc2140100a73aa237faec002e67d89fea59f24151997bb5e61233fa0","target":"graph","created_at":"2026-05-18T01:49:38Z","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":"We study the existence of analogue nonstationary spherically symmetric black holes. The prime example is the acoustic model (cf. [V], [U]). We consider also a more general class of metrics that could be useful in other physical models of analogue black and white holes.\n  We give examples of the appearance of black holes and of disappearance of white holes. We also discuss the relation between the apparent and the event horizons for the case of analogue black holes. In the end we study the inverse problem of determination of black or white holes by boundary measurements for the spherically symm","authors_text":"Gregory Eskin","cross_cats":["gr-qc","math.AP","math.MP"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math-ph","submitted_at":"2013-06-01T20:57:47Z","title":"Nonstationary analogue black holes"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1306.0149","kind":"arxiv","version":2},"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":"sha256:5d5121e98ebab4c503142b0d87c6b38c9c2a8703e59185407274dcc01df1e50a","target":"record","created_at":"2026-05-18T01:49:38Z","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":"8533bc97a16b56493832909ff3471493d97cb3b63182bbbf1245729a27179e1a","cross_cats_sorted":["gr-qc","math.AP","math.MP"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math-ph","submitted_at":"2013-06-01T20:57:47Z","title_canon_sha256":"b578a433262d1cd49376e060b20c4f6611fb608fd8e85d4a57f1d7836a796bcf"},"schema_version":"1.0","source":{"id":"1306.0149","kind":"arxiv","version":2}},"canonical_sha256":"bd27a3c9ee839ab3fea064ce71bd239c16ea896f1c6db6e41c934bbd19d95922","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"bd27a3c9ee839ab3fea064ce71bd239c16ea896f1c6db6e41c934bbd19d95922","first_computed_at":"2026-05-18T01:49:38.857822Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:49:38.857822Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"IhR1od0rzCI9jMK5EIoP0r8KXGJQf4HIhoxrmIbA+Wt/KtZ9+Cr8ynxSd5UZeVr6yy88dF32nhvCNkw20VM/Cg==","signature_status":"signed_v1","signed_at":"2026-05-18T01:49:38.859147Z","signed_message":"canonical_sha256_bytes"},"source_id":"1306.0149","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:5d5121e98ebab4c503142b0d87c6b38c9c2a8703e59185407274dcc01df1e50a","sha256:0b8990c7bc2140100a73aa237faec002e67d89fea59f24151997bb5e61233fa0"],"state_sha256":"8006693f06e8cd073030c5a326c0f1a6d59738fc12209f4cfc3b54f679c686f7"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"6a+jnBL9JnBubJe4/iYXH8tr+EDA+U7fDUmM+WiE1io0LZJBZp9Xv7QxWN/NMV8pTYOgwpi8/q65qd+3ZS1YBQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-20T13:38:27.543104Z","bundle_sha256":"d5e6f1e040ffc4241931369ed7bea113b4f36cef8a20a0768558b9f08ca89451"}}