{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:1998:DQYCYOUPN3YBNFXGFLKY2O2IVA","short_pith_number":"pith:DQYCYOUP","canonical_record":{"source":{"id":"gr-qc/9805006","kind":"arxiv","version":2},"metadata":{"license":"","primary_cat":"gr-qc","submitted_at":"1998-05-04T14:18:51Z","cross_cats_sorted":[],"title_canon_sha256":"115d093059740b7dcbcbea755c99052ad2a33dbc9342d717616424cf3c518bb0","abstract_canon_sha256":"15f60278ae7ed7499b7648b2768903fd461131e83bb6a00b7715db1c07c6ecec"},"schema_version":"1.0"},"canonical_sha256":"1c302c3a8f6ef01696e62ad58d3b48a80d8bf236dbb3f008c7d2a7464b770e3d","source":{"kind":"arxiv","id":"gr-qc/9805006","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"gr-qc/9805006","created_at":"2026-05-18T01:39:18Z"},{"alias_kind":"arxiv_version","alias_value":"gr-qc/9805006v2","created_at":"2026-05-18T01:39:18Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.gr-qc/9805006","created_at":"2026-05-18T01:39:18Z"},{"alias_kind":"pith_short_12","alias_value":"DQYCYOUPN3YB","created_at":"2026-05-18T12:25:49Z"},{"alias_kind":"pith_short_16","alias_value":"DQYCYOUPN3YBNFXG","created_at":"2026-05-18T12:25:49Z"},{"alias_kind":"pith_short_8","alias_value":"DQYCYOUP","created_at":"2026-05-18T12:25:49Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:1998:DQYCYOUPN3YBNFXGFLKY2O2IVA","target":"record","payload":{"canonical_record":{"source":{"id":"gr-qc/9805006","kind":"arxiv","version":2},"metadata":{"license":"","primary_cat":"gr-qc","submitted_at":"1998-05-04T14:18:51Z","cross_cats_sorted":[],"title_canon_sha256":"115d093059740b7dcbcbea755c99052ad2a33dbc9342d717616424cf3c518bb0","abstract_canon_sha256":"15f60278ae7ed7499b7648b2768903fd461131e83bb6a00b7715db1c07c6ecec"},"schema_version":"1.0"},"canonical_sha256":"1c302c3a8f6ef01696e62ad58d3b48a80d8bf236dbb3f008c7d2a7464b770e3d","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:39:18.593836Z","signature_b64":"hzeTXtn4ZH9DtuN6aPScWhak1WyP7uNneM6L9Y+IgzVEqy27U3+NcP4LsL75nmutPfbjdpImssdREeWSVVryBA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"1c302c3a8f6ef01696e62ad58d3b48a80d8bf236dbb3f008c7d2a7464b770e3d","last_reissued_at":"2026-05-18T01:39:18.593333Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:39:18.593333Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"gr-qc/9805006","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":"2026-05-18T01:39:18Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"oMrAIPJNjeUFjavx5PtFoegfGa8J9CeuC6PLkmw8T2E4u+haKpo9+NRXg7brX7tGMeD3tHWKgmBO086IcgqmAg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-31T22:21:11.095975Z"},"content_sha256":"7a14cf27e8a5c00eac2c55bb574553c7478fb8de58476ca00b05bd2cb667cb73","schema_version":"1.0","event_id":"sha256:7a14cf27e8a5c00eac2c55bb574553c7478fb8de58476ca00b05bd2cb667cb73"},{"event_type":"graph_snapshot","subject_pith_number":"pith:1998:DQYCYOUPN3YBNFXGFLKY2O2IVA","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Gravitational instantons admit hyper-K\\\"ahler structure","license":"","headline":"","cross_cats":[],"primary_cat":"gr-qc","authors_text":"A. N. Aliev, Y. Nutku","submitted_at":"1998-05-04T14:18:51Z","abstract_excerpt":"We construct the explicit form of three almost complex structures that a Riemannian manifold with self-dual curvature admits and show that their Nijenhuis tensors vanish so that they are integrable. This proves that gravitational instantons with self-dual curvature admit hyper-K\\\"{a}hler structure. In order to arrive at the three vector valued 1-forms defining almost complex structure, we give a spinor description of real 4-dimensional Riemanian manifolds with Euclidean signature in terms of two independent sets of 2-component spinors. This is a version of the original Newman-Penrose formalism"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"gr-qc/9805006","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":"2026-05-18T01:39:18Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"6TexxgtBxbLXA/R6Npeeni7m2ipqG/cqKBug2/HoUQgHwz3bSBCsb9+a6ETvc0E6UEyS0/mcUL8Xgfw1jqGtDg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-31T22:21:11.096642Z"},"content_sha256":"aa823455652ad40f385280aa9799e62d0088e839aa5537de1346d831788a70fc","schema_version":"1.0","event_id":"sha256:aa823455652ad40f385280aa9799e62d0088e839aa5537de1346d831788a70fc"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/DQYCYOUPN3YBNFXGFLKY2O2IVA/bundle.json","state_url":"https://pith.science/pith/DQYCYOUPN3YBNFXGFLKY2O2IVA/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/DQYCYOUPN3YBNFXGFLKY2O2IVA/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":"2026-05-31T22:21:11Z","links":{"resolver":"https://pith.science/pith/DQYCYOUPN3YBNFXGFLKY2O2IVA","bundle":"https://pith.science/pith/DQYCYOUPN3YBNFXGFLKY2O2IVA/bundle.json","state":"https://pith.science/pith/DQYCYOUPN3YBNFXGFLKY2O2IVA/state.json","well_known_bundle":"https://pith.science/.well-known/pith/DQYCYOUPN3YBNFXGFLKY2O2IVA/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:1998:DQYCYOUPN3YBNFXGFLKY2O2IVA","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":"15f60278ae7ed7499b7648b2768903fd461131e83bb6a00b7715db1c07c6ecec","cross_cats_sorted":[],"license":"","primary_cat":"gr-qc","submitted_at":"1998-05-04T14:18:51Z","title_canon_sha256":"115d093059740b7dcbcbea755c99052ad2a33dbc9342d717616424cf3c518bb0"},"schema_version":"1.0","source":{"id":"gr-qc/9805006","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"gr-qc/9805006","created_at":"2026-05-18T01:39:18Z"},{"alias_kind":"arxiv_version","alias_value":"gr-qc/9805006v2","created_at":"2026-05-18T01:39:18Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.gr-qc/9805006","created_at":"2026-05-18T01:39:18Z"},{"alias_kind":"pith_short_12","alias_value":"DQYCYOUPN3YB","created_at":"2026-05-18T12:25:49Z"},{"alias_kind":"pith_short_16","alias_value":"DQYCYOUPN3YBNFXG","created_at":"2026-05-18T12:25:49Z"},{"alias_kind":"pith_short_8","alias_value":"DQYCYOUP","created_at":"2026-05-18T12:25:49Z"}],"graph_snapshots":[{"event_id":"sha256:aa823455652ad40f385280aa9799e62d0088e839aa5537de1346d831788a70fc","target":"graph","created_at":"2026-05-18T01:39:18Z","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 construct the explicit form of three almost complex structures that a Riemannian manifold with self-dual curvature admits and show that their Nijenhuis tensors vanish so that they are integrable. This proves that gravitational instantons with self-dual curvature admit hyper-K\\\"{a}hler structure. In order to arrive at the three vector valued 1-forms defining almost complex structure, we give a spinor description of real 4-dimensional Riemanian manifolds with Euclidean signature in terms of two independent sets of 2-component spinors. This is a version of the original Newman-Penrose formalism","authors_text":"A. N. Aliev, Y. Nutku","cross_cats":[],"headline":"","license":"","primary_cat":"gr-qc","submitted_at":"1998-05-04T14:18:51Z","title":"Gravitational instantons admit hyper-K\\\"ahler structure"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"gr-qc/9805006","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":"sha256:7a14cf27e8a5c00eac2c55bb574553c7478fb8de58476ca00b05bd2cb667cb73","target":"record","created_at":"2026-05-18T01:39:18Z","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":"15f60278ae7ed7499b7648b2768903fd461131e83bb6a00b7715db1c07c6ecec","cross_cats_sorted":[],"license":"","primary_cat":"gr-qc","submitted_at":"1998-05-04T14:18:51Z","title_canon_sha256":"115d093059740b7dcbcbea755c99052ad2a33dbc9342d717616424cf3c518bb0"},"schema_version":"1.0","source":{"id":"gr-qc/9805006","kind":"arxiv","version":2}},"canonical_sha256":"1c302c3a8f6ef01696e62ad58d3b48a80d8bf236dbb3f008c7d2a7464b770e3d","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"1c302c3a8f6ef01696e62ad58d3b48a80d8bf236dbb3f008c7d2a7464b770e3d","first_computed_at":"2026-05-18T01:39:18.593333Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:39:18.593333Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"hzeTXtn4ZH9DtuN6aPScWhak1WyP7uNneM6L9Y+IgzVEqy27U3+NcP4LsL75nmutPfbjdpImssdREeWSVVryBA==","signature_status":"signed_v1","signed_at":"2026-05-18T01:39:18.593836Z","signed_message":"canonical_sha256_bytes"},"source_id":"gr-qc/9805006","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:7a14cf27e8a5c00eac2c55bb574553c7478fb8de58476ca00b05bd2cb667cb73","sha256:aa823455652ad40f385280aa9799e62d0088e839aa5537de1346d831788a70fc"],"state_sha256":"91aa6824363ac8a4c71dfeba3150720f187c76dccacdcaa9891a01654db0d58b"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"Vls/MO3BxGiLQiLxNXTW/BpRHW6Dcud7FmVeNHGBQ2KQgGJBrxr7o7SFvdg8hhrDamjBx7EonYn6My1B9tsnDg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-31T22:21:11.100741Z","bundle_sha256":"cd3370e9765560dd096776c25233794d2d7f3c49c7a5b09a6f8bfcf4c27b0a30"}}