{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2005:GPOLWBXRJWQR3HPXYG37CC76OS","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":"bcb80f4b1c5bcc11c228cb9b1249846a6d4f42df10396f44d0666e03697fabbd","cross_cats_sorted":["gr-qc","hep-th"],"license":"","primary_cat":"astro-ph","submitted_at":"2005-06-28T11:05:32Z","title_canon_sha256":"887fb789b3af798dd2a5769098be97bb310d13c306128adfcd2c55809de6ab53"},"schema_version":"1.0","source":{"id":"astro-ph/0506692","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"astro-ph/0506692","created_at":"2026-05-18T03:24:40Z"},{"alias_kind":"arxiv_version","alias_value":"astro-ph/0506692v1","created_at":"2026-05-18T03:24:40Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.astro-ph/0506692","created_at":"2026-05-18T03:24:40Z"},{"alias_kind":"pith_short_12","alias_value":"GPOLWBXRJWQR","created_at":"2026-05-18T12:25:53Z"},{"alias_kind":"pith_short_16","alias_value":"GPOLWBXRJWQR3HPX","created_at":"2026-05-18T12:25:53Z"},{"alias_kind":"pith_short_8","alias_value":"GPOLWBXR","created_at":"2026-05-18T12:25:53Z"}],"graph_snapshots":[{"event_id":"sha256:b5011c06716861dbcbaa38572ee9ee2204db8c34305cf04ee2dcfe69f915d11d","target":"graph","created_at":"2026-05-18T03:24:40Z","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":"Modified theories of gravity have recently been studied by several authors as possibly viable alternatives to the cosmological concordance model. Such theories attempt to explain the accelerating expansion of the universe by changing the theory of gravity, instead of introducing dark energy. In particular, a class of models based on higher order curvature invariants, so-called $f(R)$ gravity models, has drawn attention. In this letter we show that within this framework, the expansion history of the universe does not uniquely determine the form of the gravitational action and it can be radicall","authors_text":"I. Vilja, T. Multamaki","cross_cats":["gr-qc","hep-th"],"headline":"","license":"","primary_cat":"astro-ph","submitted_at":"2005-06-28T11:05:32Z","title":"Cosmological expansion and the uniqueness of gravitational action"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/0506692","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":"sha256:0b142c35b5c0155ad7a4d200f0f9d8683a433c04fa96c0e69ff305567cf3411f","target":"record","created_at":"2026-05-18T03:24:40Z","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":"bcb80f4b1c5bcc11c228cb9b1249846a6d4f42df10396f44d0666e03697fabbd","cross_cats_sorted":["gr-qc","hep-th"],"license":"","primary_cat":"astro-ph","submitted_at":"2005-06-28T11:05:32Z","title_canon_sha256":"887fb789b3af798dd2a5769098be97bb310d13c306128adfcd2c55809de6ab53"},"schema_version":"1.0","source":{"id":"astro-ph/0506692","kind":"arxiv","version":1}},"canonical_sha256":"33dcbb06f14da11d9df7c1b7f10bfe749cae4d9168779bf7b18c18327bc8548e","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"33dcbb06f14da11d9df7c1b7f10bfe749cae4d9168779bf7b18c18327bc8548e","first_computed_at":"2026-05-18T03:24:40.298746Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T03:24:40.298746Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"IPBvLw4RdwrGI9OxsyxGyhnQYabmT0NIOTShTTIrdC6mFeraK27ul2lZ8ieHJxvE3usmpRwljR83wogKCOfqDA==","signature_status":"signed_v1","signed_at":"2026-05-18T03:24:40.299651Z","signed_message":"canonical_sha256_bytes"},"source_id":"astro-ph/0506692","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:0b142c35b5c0155ad7a4d200f0f9d8683a433c04fa96c0e69ff305567cf3411f","sha256:b5011c06716861dbcbaa38572ee9ee2204db8c34305cf04ee2dcfe69f915d11d"],"state_sha256":"32f8b297e8d50ef430d5eb902021364f3e7b10cda87b2a70376063137cc433ac"}