{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2004:FI4V2YUZCLUGCPMJ3HM676V3FV","short_pith_number":"pith:FI4V2YUZ","canonical_record":{"source":{"id":"physics/0409155","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.class-ph","submitted_at":"2004-09-29T15:49:22Z","cross_cats_sorted":["gr-qc"],"title_canon_sha256":"e56c80ff92cf4f1524f2e8883caa8cac1c7be42f2d54c747328313c1de185547","abstract_canon_sha256":"844de23debaf64a2f25e8d282e49a0d258071690dcb48686c0e050cfba5bbfb4"},"schema_version":"1.0"},"canonical_sha256":"2a395d629912e8613d89d9d9effabb2d764fd25c8d33c372ced607cc65dbf3a9","source":{"kind":"arxiv","id":"physics/0409155","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"physics/0409155","created_at":"2026-07-04T15:31:51Z"},{"alias_kind":"arxiv_version","alias_value":"physics/0409155v2","created_at":"2026-07-04T15:31:51Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.physics/0409155","created_at":"2026-07-04T15:31:51Z"},{"alias_kind":"pith_short_12","alias_value":"FI4V2YUZCLUG","created_at":"2026-07-04T15:31:51Z"},{"alias_kind":"pith_short_16","alias_value":"FI4V2YUZCLUGCPMJ","created_at":"2026-07-04T15:31:51Z"},{"alias_kind":"pith_short_8","alias_value":"FI4V2YUZ","created_at":"2026-07-04T15:31:51Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2004:FI4V2YUZCLUGCPMJ3HM676V3FV","target":"record","payload":{"canonical_record":{"source":{"id":"physics/0409155","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.class-ph","submitted_at":"2004-09-29T15:49:22Z","cross_cats_sorted":["gr-qc"],"title_canon_sha256":"e56c80ff92cf4f1524f2e8883caa8cac1c7be42f2d54c747328313c1de185547","abstract_canon_sha256":"844de23debaf64a2f25e8d282e49a0d258071690dcb48686c0e050cfba5bbfb4"},"schema_version":"1.0"},"canonical_sha256":"2a395d629912e8613d89d9d9effabb2d764fd25c8d33c372ced607cc65dbf3a9","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-04T15:31:51.018341Z","signature_b64":"c3v+U4YgErLR5HTvR/k02DiVJ4wQ1MUMmvRlrFxuh8ythE7LRsnJ09V+/1Uqk2aWDlR5p1I9RQcNV0HF5zkSBQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"2a395d629912e8613d89d9d9effabb2d764fd25c8d33c372ced607cc65dbf3a9","last_reissued_at":"2026-07-04T15:31:51.017907Z","signature_status":"signed_v1","first_computed_at":"2026-07-04T15:31:51.017907Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"physics/0409155","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":"2026-07-04T15:31:51Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"Qy/KiZDxOmSbQcy8pj7IB6JM77EqAWQYb1Z2a8Y88i0AGHU3cqnZKcotBAHjGigjt62JWKk0w7kSiiWO9KJ0BA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-07-28T02:12:23.345954Z"},"content_sha256":"ac44257e51d0ce223fa317f5ea85df16a015f4d1398fa85154221d5f81423ca1","schema_version":"1.0","event_id":"sha256:ac44257e51d0ce223fa317f5ea85df16a015f4d1398fa85154221d5f81423ca1"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2004:FI4V2YUZCLUGCPMJ3HM676V3FV","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"On possible skewon effects on light propagation","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["gr-qc"],"primary_cat":"physics.class-ph","authors_text":"Friedrich W. Hehl, Yuri N. Obukhov","submitted_at":"2004-09-29T15:49:22Z","abstract_excerpt":"We start from a local and linear spacetime relation between the electromagnetic excitation and the field strength. Then we study the generally covariant Fresnel surfaces for light rays and light waves. The metric and the connection of spacetime are left unspecified. Accordingly, our framework is ideally suited for a search of possible violations of the Lorentz symmetry in the photon sector of the extended standard model. We discuss how the skewon part of the constitutive tensor, if suitably parametrized, influences the Fresnel surfaces and disturbs the light cones of vacuum electrodynamics. Co"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"physics/0409155","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/physics/0409155/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"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-04T15:31:51Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"LXQAHESWa4gjK90MKyA3cNRFxcsd+u9GDU1Ky0WdDO2mi5saTJog3BY63NNfXCxXoOrP5xISHVHXlH8ioZe7BQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-07-28T02:12:23.346339Z"},"content_sha256":"5decce1bcc9e8141e556bf99bfec818e352a0481747e95b722c93c5e62239447","schema_version":"1.0","event_id":"sha256:5decce1bcc9e8141e556bf99bfec818e352a0481747e95b722c93c5e62239447"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/FI4V2YUZCLUGCPMJ3HM676V3FV/bundle.json","state_url":"https://pith.science/pith/FI4V2YUZCLUGCPMJ3HM676V3FV/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/FI4V2YUZCLUGCPMJ3HM676V3FV/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":"2026-07-28T02:12:23Z","links":{"resolver":"https://pith.science/pith/FI4V2YUZCLUGCPMJ3HM676V3FV","bundle":"https://pith.science/pith/FI4V2YUZCLUGCPMJ3HM676V3FV/bundle.json","state":"https://pith.science/pith/FI4V2YUZCLUGCPMJ3HM676V3FV/state.json","well_known_bundle":"https://pith.science/.well-known/pith/FI4V2YUZCLUGCPMJ3HM676V3FV/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2004:FI4V2YUZCLUGCPMJ3HM676V3FV","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":"844de23debaf64a2f25e8d282e49a0d258071690dcb48686c0e050cfba5bbfb4","cross_cats_sorted":["gr-qc"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.class-ph","submitted_at":"2004-09-29T15:49:22Z","title_canon_sha256":"e56c80ff92cf4f1524f2e8883caa8cac1c7be42f2d54c747328313c1de185547"},"schema_version":"1.0","source":{"id":"physics/0409155","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"physics/0409155","created_at":"2026-07-04T15:31:51Z"},{"alias_kind":"arxiv_version","alias_value":"physics/0409155v2","created_at":"2026-07-04T15:31:51Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.physics/0409155","created_at":"2026-07-04T15:31:51Z"},{"alias_kind":"pith_short_12","alias_value":"FI4V2YUZCLUG","created_at":"2026-07-04T15:31:51Z"},{"alias_kind":"pith_short_16","alias_value":"FI4V2YUZCLUGCPMJ","created_at":"2026-07-04T15:31:51Z"},{"alias_kind":"pith_short_8","alias_value":"FI4V2YUZ","created_at":"2026-07-04T15:31:51Z"}],"graph_snapshots":[{"event_id":"sha256:5decce1bcc9e8141e556bf99bfec818e352a0481747e95b722c93c5e62239447","target":"graph","created_at":"2026-07-04T15:31:51Z","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"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/physics/0409155/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"We start from a local and linear spacetime relation between the electromagnetic excitation and the field strength. Then we study the generally covariant Fresnel surfaces for light rays and light waves. The metric and the connection of spacetime are left unspecified. Accordingly, our framework is ideally suited for a search of possible violations of the Lorentz symmetry in the photon sector of the extended standard model. We discuss how the skewon part of the constitutive tensor, if suitably parametrized, influences the Fresnel surfaces and disturbs the light cones of vacuum electrodynamics. Co","authors_text":"Friedrich W. Hehl, Yuri N. Obukhov","cross_cats":["gr-qc"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.class-ph","submitted_at":"2004-09-29T15:49:22Z","title":"On possible skewon effects on light propagation"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"physics/0409155","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:ac44257e51d0ce223fa317f5ea85df16a015f4d1398fa85154221d5f81423ca1","target":"record","created_at":"2026-07-04T15:31:51Z","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":"844de23debaf64a2f25e8d282e49a0d258071690dcb48686c0e050cfba5bbfb4","cross_cats_sorted":["gr-qc"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.class-ph","submitted_at":"2004-09-29T15:49:22Z","title_canon_sha256":"e56c80ff92cf4f1524f2e8883caa8cac1c7be42f2d54c747328313c1de185547"},"schema_version":"1.0","source":{"id":"physics/0409155","kind":"arxiv","version":2}},"canonical_sha256":"2a395d629912e8613d89d9d9effabb2d764fd25c8d33c372ced607cc65dbf3a9","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"2a395d629912e8613d89d9d9effabb2d764fd25c8d33c372ced607cc65dbf3a9","first_computed_at":"2026-07-04T15:31:51.017907Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-04T15:31:51.017907Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"c3v+U4YgErLR5HTvR/k02DiVJ4wQ1MUMmvRlrFxuh8ythE7LRsnJ09V+/1Uqk2aWDlR5p1I9RQcNV0HF5zkSBQ==","signature_status":"signed_v1","signed_at":"2026-07-04T15:31:51.018341Z","signed_message":"canonical_sha256_bytes"},"source_id":"physics/0409155","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:ac44257e51d0ce223fa317f5ea85df16a015f4d1398fa85154221d5f81423ca1","sha256:5decce1bcc9e8141e556bf99bfec818e352a0481747e95b722c93c5e62239447"],"state_sha256":"b81fd01a947cf8254aec29a38fffaac54db487a1de39d3c8f88b9e23024e846d"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"xb8v6C7b2UkvwuBKGA2bkUnW70yi6D3PIeSXuLOhKOgHlL8ZzLMMcIj0WzDvwSTatFYTpIDQanh+Axp13FjLAA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-07-28T02:12:23.348514Z","bundle_sha256":"a154e5677745557c7e215d6e7414a250eec9961dd04e23cf0b6f0cf4ff6a9ec5"}}