{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2014:LQGIKDGQZXIQ5DMDIRI2ERUF5N","short_pith_number":"pith:LQGIKDGQ","canonical_record":{"source":{"id":"1409.2170","kind":"arxiv","version":4},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.LO","submitted_at":"2014-09-07T21:51:21Z","cross_cats_sorted":["cs.CC","math.CO"],"title_canon_sha256":"a7cf4d44ec26f13351cf34636782dd0b519385302ec75c2e311815f2889b0faa","abstract_canon_sha256":"b9b6dae760302f2e47f551356a6fcd4b53f2f8ebba7eb30ac363a73234577507"},"schema_version":"1.0"},"canonical_sha256":"5c0c850cd0cdd10e8d834451a24685eb513fa9e0cfa20ebc5754c718999e0f91","source":{"kind":"arxiv","id":"1409.2170","version":4},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1409.2170","created_at":"2026-05-18T00:59:28Z"},{"alias_kind":"arxiv_version","alias_value":"1409.2170v4","created_at":"2026-05-18T00:59:28Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1409.2170","created_at":"2026-05-18T00:59:28Z"},{"alias_kind":"pith_short_12","alias_value":"LQGIKDGQZXIQ","created_at":"2026-05-18T12:28:38Z"},{"alias_kind":"pith_short_16","alias_value":"LQGIKDGQZXIQ5DMD","created_at":"2026-05-18T12:28:38Z"},{"alias_kind":"pith_short_8","alias_value":"LQGIKDGQ","created_at":"2026-05-18T12:28:38Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2014:LQGIKDGQZXIQ5DMDIRI2ERUF5N","target":"record","payload":{"canonical_record":{"source":{"id":"1409.2170","kind":"arxiv","version":4},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.LO","submitted_at":"2014-09-07T21:51:21Z","cross_cats_sorted":["cs.CC","math.CO"],"title_canon_sha256":"a7cf4d44ec26f13351cf34636782dd0b519385302ec75c2e311815f2889b0faa","abstract_canon_sha256":"b9b6dae760302f2e47f551356a6fcd4b53f2f8ebba7eb30ac363a73234577507"},"schema_version":"1.0"},"canonical_sha256":"5c0c850cd0cdd10e8d834451a24685eb513fa9e0cfa20ebc5754c718999e0f91","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T00:59:28.025562Z","signature_b64":"7dEduJrhoYZPHd0rLT/wMm6VuwoGrdAr+YM4hAx3qR/NVVHjVXvmrfGUAsvN0SoIi3PkbhJ/qGlBre+ofJ4ACQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"5c0c850cd0cdd10e8d834451a24685eb513fa9e0cfa20ebc5754c718999e0f91","last_reissued_at":"2026-05-18T00:59:28.025011Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T00:59:28.025011Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1409.2170","source_version":4,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T00:59:28Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"6zTNbac12mEiOcqNh9LaFJI2zZJQNvN4b08WVrKx8V2ILbZHl9jEcN0OmS2hAV6JV/NprQ324AxYt9aPeEQjAA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-30T18:31:54.633005Z"},"content_sha256":"296f12234f7b9cb2b082f7b0b4a81f438065b4c5ad7d1b26a563d8b4194b300b","schema_version":"1.0","event_id":"sha256:296f12234f7b9cb2b082f7b0b4a81f438065b4c5ad7d1b26a563d8b4194b300b"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2014:LQGIKDGQZXIQ5DMDIRI2ERUF5N","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"The universal homogeneous binary tree","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["cs.CC","math.CO"],"primary_cat":"math.LO","authors_text":"Andr\\'as Pongr\\'acz, David Bradley-Williams, Manuel Bodirsky, Michael Pinsker","submitted_at":"2014-09-07T21:51:21Z","abstract_excerpt":"A partial order is called semilinear iff the upper bounds of each element are linearly ordered and any two elements have a common upper bound. There exists, up to isomorphism, a unique countable existentially closed semilinear order, which we denote by S2. We study the reducts of S2, that is, the relational structures with the same domain as S2 all of whose relations are first-order definable in S2. Our main result is a classification of the model-complete cores of the reducts of S2. From this, we also obtain a classification of reducts up to first-order interdefinability, which is equivalent "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1409.2170","kind":"arxiv","version":4},"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":"2026-05-18T00:59:28Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"XgCcX+IHiw2bxx/I9pdLdmhKCo+2lphhTdzi1LR/5+jpgD42kIAsXoA5kRf+cqwTEdY8AmZntdUIyOp6ssB6Dw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-30T18:31:54.633664Z"},"content_sha256":"724ca1f7fb1b4417be6348792c543289bc650408ea73edaadf0393570040ac4e","schema_version":"1.0","event_id":"sha256:724ca1f7fb1b4417be6348792c543289bc650408ea73edaadf0393570040ac4e"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/LQGIKDGQZXIQ5DMDIRI2ERUF5N/bundle.json","state_url":"https://pith.science/pith/LQGIKDGQZXIQ5DMDIRI2ERUF5N/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/LQGIKDGQZXIQ5DMDIRI2ERUF5N/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":"2026-05-30T18:31:54Z","links":{"resolver":"https://pith.science/pith/LQGIKDGQZXIQ5DMDIRI2ERUF5N","bundle":"https://pith.science/pith/LQGIKDGQZXIQ5DMDIRI2ERUF5N/bundle.json","state":"https://pith.science/pith/LQGIKDGQZXIQ5DMDIRI2ERUF5N/state.json","well_known_bundle":"https://pith.science/.well-known/pith/LQGIKDGQZXIQ5DMDIRI2ERUF5N/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2014:LQGIKDGQZXIQ5DMDIRI2ERUF5N","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":"b9b6dae760302f2e47f551356a6fcd4b53f2f8ebba7eb30ac363a73234577507","cross_cats_sorted":["cs.CC","math.CO"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.LO","submitted_at":"2014-09-07T21:51:21Z","title_canon_sha256":"a7cf4d44ec26f13351cf34636782dd0b519385302ec75c2e311815f2889b0faa"},"schema_version":"1.0","source":{"id":"1409.2170","kind":"arxiv","version":4}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1409.2170","created_at":"2026-05-18T00:59:28Z"},{"alias_kind":"arxiv_version","alias_value":"1409.2170v4","created_at":"2026-05-18T00:59:28Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1409.2170","created_at":"2026-05-18T00:59:28Z"},{"alias_kind":"pith_short_12","alias_value":"LQGIKDGQZXIQ","created_at":"2026-05-18T12:28:38Z"},{"alias_kind":"pith_short_16","alias_value":"LQGIKDGQZXIQ5DMD","created_at":"2026-05-18T12:28:38Z"},{"alias_kind":"pith_short_8","alias_value":"LQGIKDGQ","created_at":"2026-05-18T12:28:38Z"}],"graph_snapshots":[{"event_id":"sha256:724ca1f7fb1b4417be6348792c543289bc650408ea73edaadf0393570040ac4e","target":"graph","created_at":"2026-05-18T00:59:28Z","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":"A partial order is called semilinear iff the upper bounds of each element are linearly ordered and any two elements have a common upper bound. There exists, up to isomorphism, a unique countable existentially closed semilinear order, which we denote by S2. We study the reducts of S2, that is, the relational structures with the same domain as S2 all of whose relations are first-order definable in S2. Our main result is a classification of the model-complete cores of the reducts of S2. From this, we also obtain a classification of reducts up to first-order interdefinability, which is equivalent ","authors_text":"Andr\\'as Pongr\\'acz, David Bradley-Williams, Manuel Bodirsky, Michael Pinsker","cross_cats":["cs.CC","math.CO"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.LO","submitted_at":"2014-09-07T21:51:21Z","title":"The universal homogeneous binary tree"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1409.2170","kind":"arxiv","version":4},"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":"sha256:296f12234f7b9cb2b082f7b0b4a81f438065b4c5ad7d1b26a563d8b4194b300b","target":"record","created_at":"2026-05-18T00:59:28Z","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":"b9b6dae760302f2e47f551356a6fcd4b53f2f8ebba7eb30ac363a73234577507","cross_cats_sorted":["cs.CC","math.CO"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.LO","submitted_at":"2014-09-07T21:51:21Z","title_canon_sha256":"a7cf4d44ec26f13351cf34636782dd0b519385302ec75c2e311815f2889b0faa"},"schema_version":"1.0","source":{"id":"1409.2170","kind":"arxiv","version":4}},"canonical_sha256":"5c0c850cd0cdd10e8d834451a24685eb513fa9e0cfa20ebc5754c718999e0f91","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"5c0c850cd0cdd10e8d834451a24685eb513fa9e0cfa20ebc5754c718999e0f91","first_computed_at":"2026-05-18T00:59:28.025011Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:59:28.025011Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"7dEduJrhoYZPHd0rLT/wMm6VuwoGrdAr+YM4hAx3qR/NVVHjVXvmrfGUAsvN0SoIi3PkbhJ/qGlBre+ofJ4ACQ==","signature_status":"signed_v1","signed_at":"2026-05-18T00:59:28.025562Z","signed_message":"canonical_sha256_bytes"},"source_id":"1409.2170","source_kind":"arxiv","source_version":4}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:296f12234f7b9cb2b082f7b0b4a81f438065b4c5ad7d1b26a563d8b4194b300b","sha256:724ca1f7fb1b4417be6348792c543289bc650408ea73edaadf0393570040ac4e"],"state_sha256":"c9581f77b35af6da796e40ffc1daefb524783b42cdd6c81aaa1718b799037ef6"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"Dbg9aFw+3q5IFVgj5sKOmxtW3RR/M5Q5+OLh+hHr8c5RSAATTxgPWCwwkPPkoFwjz+p+IsU18qig7Js02pnsBQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-30T18:31:54.637355Z","bundle_sha256":"86f4f37659dcc2259fbabae3e644730340a627246a501d408b78e035c5aee1e0"}}