{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2013:BVJDP2OGOSMWERHHUKNBFY7T4U","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":"407d6b63e06a8da2b1a386f7a5401bbba8752a2bd5377900f798846eaa5b0930","cross_cats_sorted":["math-ph","math.MP"],"license":"http://creativecommons.org/licenses/by-sa/4.0/","primary_cat":"nlin.SI","submitted_at":"2013-12-05T05:43:02Z","title_canon_sha256":"2ca24bba440f5c5e0a53e78b17859c47b1dfc52ee877a90beb654a312b2be93f"},"schema_version":"1.0","source":{"id":"1312.1440","kind":"arxiv","version":3}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1312.1440","created_at":"2026-05-18T00:16:57Z"},{"alias_kind":"arxiv_version","alias_value":"1312.1440v3","created_at":"2026-05-18T00:16:57Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1312.1440","created_at":"2026-05-18T00:16:57Z"},{"alias_kind":"pith_short_12","alias_value":"BVJDP2OGOSMW","created_at":"2026-05-18T12:27:40Z"},{"alias_kind":"pith_short_16","alias_value":"BVJDP2OGOSMWERHH","created_at":"2026-05-18T12:27:40Z"},{"alias_kind":"pith_short_8","alias_value":"BVJDP2OG","created_at":"2026-05-18T12:27:40Z"}],"graph_snapshots":[{"event_id":"sha256:c957eff036dde0946db4aafc2df3dc5da4caac741526b6b0183c58b7b5641c83","target":"graph","created_at":"2026-05-18T00:16:57Z","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":"For integrable systems in the sense of multidimensional consistency (MDC) we can consider the Lagrangian as a form, which is closed on solutions of the equations of motion. For 2-dimensional systems, described by partial difference equations with two independent variables, MDC allows us to define an action on arbitrary 2-dimensional surfaces embedded in a higher dimensional space of independent variables, where the action is not only a functional of the field variables but also the choice of surface. It is then natural to propose that the system should be derived from a variational principle w","authors_text":"Frank W. Nijhoff, Sarah B. Lobb","cross_cats":["math-ph","math.MP"],"headline":"","license":"http://creativecommons.org/licenses/by-sa/4.0/","primary_cat":"nlin.SI","submitted_at":"2013-12-05T05:43:02Z","title":"A Variational Principle for Discrete Integrable Systems"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1312.1440","kind":"arxiv","version":3},"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:f5f7477621e666ed7e43fe0d761633bea3e1fb91f6230a6e5a0ad3952b532982","target":"record","created_at":"2026-05-18T00:16:57Z","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":"407d6b63e06a8da2b1a386f7a5401bbba8752a2bd5377900f798846eaa5b0930","cross_cats_sorted":["math-ph","math.MP"],"license":"http://creativecommons.org/licenses/by-sa/4.0/","primary_cat":"nlin.SI","submitted_at":"2013-12-05T05:43:02Z","title_canon_sha256":"2ca24bba440f5c5e0a53e78b17859c47b1dfc52ee877a90beb654a312b2be93f"},"schema_version":"1.0","source":{"id":"1312.1440","kind":"arxiv","version":3}},"canonical_sha256":"0d5237e9c674996244e7a29a12e3f3e523fe7d34a66e1b35eb16db555c7e0f0d","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"0d5237e9c674996244e7a29a12e3f3e523fe7d34a66e1b35eb16db555c7e0f0d","first_computed_at":"2026-05-18T00:16:57.052194Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:16:57.052194Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"11JvWtHcGmbCAJUOXx7qtPN8hoXgPEka9w+OfR2WgDq8Wky9XCIj9PxQrCsJcO7dmtYs/UrXdQbE1cOlxEJFAw==","signature_status":"signed_v1","signed_at":"2026-05-18T00:16:57.052958Z","signed_message":"canonical_sha256_bytes"},"source_id":"1312.1440","source_kind":"arxiv","source_version":3}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:f5f7477621e666ed7e43fe0d761633bea3e1fb91f6230a6e5a0ad3952b532982","sha256:c957eff036dde0946db4aafc2df3dc5da4caac741526b6b0183c58b7b5641c83"],"state_sha256":"adf6facef0980a28046c5d3949e1bb9ce3d719cda9c2f37a1c0ef2216b8138ca"}