{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2018:U7DS4ZBSVU2JXKSE5QKDMK4PXN","short_pith_number":"pith:U7DS4ZBS","canonical_record":{"source":{"id":"1809.03112","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CL","submitted_at":"2018-09-10T03:02:46Z","cross_cats_sorted":[],"title_canon_sha256":"a6045febc5c0eb5aadf7eecca5ebae7cb33259fb6240671bd389e9ff132eb850","abstract_canon_sha256":"c5e9471040439690ccae222d43f03ee365de091caf213bde105e8ef198e1531a"},"schema_version":"1.0"},"canonical_sha256":"a7c72e6432ad349baa44ec14362b8fbb552a1eadd8d972cc14548ffbf42d0e9e","source":{"kind":"arxiv","id":"1809.03112","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1809.03112","created_at":"2026-05-18T00:06:09Z"},{"alias_kind":"arxiv_version","alias_value":"1809.03112v1","created_at":"2026-05-18T00:06:09Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1809.03112","created_at":"2026-05-18T00:06:09Z"},{"alias_kind":"pith_short_12","alias_value":"U7DS4ZBSVU2J","created_at":"2026-05-18T12:32:56Z"},{"alias_kind":"pith_short_16","alias_value":"U7DS4ZBSVU2JXKSE","created_at":"2026-05-18T12:32:56Z"},{"alias_kind":"pith_short_8","alias_value":"U7DS4ZBS","created_at":"2026-05-18T12:32:56Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2018:U7DS4ZBSVU2JXKSE5QKDMK4PXN","target":"record","payload":{"canonical_record":{"source":{"id":"1809.03112","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CL","submitted_at":"2018-09-10T03:02:46Z","cross_cats_sorted":[],"title_canon_sha256":"a6045febc5c0eb5aadf7eecca5ebae7cb33259fb6240671bd389e9ff132eb850","abstract_canon_sha256":"c5e9471040439690ccae222d43f03ee365de091caf213bde105e8ef198e1531a"},"schema_version":"1.0"},"canonical_sha256":"a7c72e6432ad349baa44ec14362b8fbb552a1eadd8d972cc14548ffbf42d0e9e","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T00:06:09.944900Z","signature_b64":"NREWNa3fFFUzV+nBmK2RlF/P3VH7lsxi4ae0F3SMowmAeD8Q0yeysFjQQjm6QvQqa6Q7JtNe6OAFw0pyx5gJCg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"a7c72e6432ad349baa44ec14362b8fbb552a1eadd8d972cc14548ffbf42d0e9e","last_reissued_at":"2026-05-18T00:06:09.944176Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T00:06:09.944176Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1809.03112","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T00:06:09Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"FrSOzL8wHMhQeZJItxqMRrZ0QZJjVNoK5wTon5wEy93Mbk3ywEkmpkHfxDfaRMozNSGQgFbZQwrF0VuzYug7AQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-28T13:36:57.559753Z"},"content_sha256":"719a393b5dbe2d8d2d1ea7e87fc0af53d6d55395c5251e76f8cc1de990ba65e2","schema_version":"1.0","event_id":"sha256:719a393b5dbe2d8d2d1ea7e87fc0af53d6d55395c5251e76f8cc1de990ba65e2"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2018:U7DS4ZBSVU2JXKSE5QKDMK4PXN","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Depth-bounding is effective: Improvements and evaluation of unsupervised PCFG induction","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cs.CL","authors_text":"Finale Doshi-Velez, Lane Schwartz, Lifeng Jin, Timothy Miller, William Schuler","submitted_at":"2018-09-10T03:02:46Z","abstract_excerpt":"There have been several recent attempts to improve the accuracy of grammar induction systems by bounding the recursive complexity of the induction model (Ponvert et al., 2011; Noji and Johnson, 2016; Shain et al., 2016; Jin et al., 2018). Modern depth-bounded grammar inducers have been shown to be more accurate than early unbounded PCFG inducers, but this technique has never been compared against unbounded induction within the same system, in part because most previous depth-bounding models are built around sequence models, the complexity of which grows exponentially with the maximum allowed d"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1809.03112","kind":"arxiv","version":1},"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":"2026-05-18T00:06:09Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"NYOnh4991sAzKX187jlbniywoUudyChdk7o8mzReNVoJXphgM4b5fkDZggcu7jbdABhpmAe6mRAxRgGekGlmDw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-28T13:36:57.560398Z"},"content_sha256":"216104805ae61fb0c3665c608c76f2bc93c28376e5b7ff654123b7092bd15d56","schema_version":"1.0","event_id":"sha256:216104805ae61fb0c3665c608c76f2bc93c28376e5b7ff654123b7092bd15d56"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/U7DS4ZBSVU2JXKSE5QKDMK4PXN/bundle.json","state_url":"https://pith.science/pith/U7DS4ZBSVU2JXKSE5QKDMK4PXN/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/U7DS4ZBSVU2JXKSE5QKDMK4PXN/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":"2026-05-28T13:36:57Z","links":{"resolver":"https://pith.science/pith/U7DS4ZBSVU2JXKSE5QKDMK4PXN","bundle":"https://pith.science/pith/U7DS4ZBSVU2JXKSE5QKDMK4PXN/bundle.json","state":"https://pith.science/pith/U7DS4ZBSVU2JXKSE5QKDMK4PXN/state.json","well_known_bundle":"https://pith.science/.well-known/pith/U7DS4ZBSVU2JXKSE5QKDMK4PXN/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2018:U7DS4ZBSVU2JXKSE5QKDMK4PXN","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":"c5e9471040439690ccae222d43f03ee365de091caf213bde105e8ef198e1531a","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CL","submitted_at":"2018-09-10T03:02:46Z","title_canon_sha256":"a6045febc5c0eb5aadf7eecca5ebae7cb33259fb6240671bd389e9ff132eb850"},"schema_version":"1.0","source":{"id":"1809.03112","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1809.03112","created_at":"2026-05-18T00:06:09Z"},{"alias_kind":"arxiv_version","alias_value":"1809.03112v1","created_at":"2026-05-18T00:06:09Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1809.03112","created_at":"2026-05-18T00:06:09Z"},{"alias_kind":"pith_short_12","alias_value":"U7DS4ZBSVU2J","created_at":"2026-05-18T12:32:56Z"},{"alias_kind":"pith_short_16","alias_value":"U7DS4ZBSVU2JXKSE","created_at":"2026-05-18T12:32:56Z"},{"alias_kind":"pith_short_8","alias_value":"U7DS4ZBS","created_at":"2026-05-18T12:32:56Z"}],"graph_snapshots":[{"event_id":"sha256:216104805ae61fb0c3665c608c76f2bc93c28376e5b7ff654123b7092bd15d56","target":"graph","created_at":"2026-05-18T00:06:09Z","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":"There have been several recent attempts to improve the accuracy of grammar induction systems by bounding the recursive complexity of the induction model (Ponvert et al., 2011; Noji and Johnson, 2016; Shain et al., 2016; Jin et al., 2018). Modern depth-bounded grammar inducers have been shown to be more accurate than early unbounded PCFG inducers, but this technique has never been compared against unbounded induction within the same system, in part because most previous depth-bounding models are built around sequence models, the complexity of which grows exponentially with the maximum allowed d","authors_text":"Finale Doshi-Velez, Lane Schwartz, Lifeng Jin, Timothy Miller, William Schuler","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CL","submitted_at":"2018-09-10T03:02:46Z","title":"Depth-bounding is effective: Improvements and evaluation of unsupervised PCFG induction"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1809.03112","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":"sha256:719a393b5dbe2d8d2d1ea7e87fc0af53d6d55395c5251e76f8cc1de990ba65e2","target":"record","created_at":"2026-05-18T00:06:09Z","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":"c5e9471040439690ccae222d43f03ee365de091caf213bde105e8ef198e1531a","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CL","submitted_at":"2018-09-10T03:02:46Z","title_canon_sha256":"a6045febc5c0eb5aadf7eecca5ebae7cb33259fb6240671bd389e9ff132eb850"},"schema_version":"1.0","source":{"id":"1809.03112","kind":"arxiv","version":1}},"canonical_sha256":"a7c72e6432ad349baa44ec14362b8fbb552a1eadd8d972cc14548ffbf42d0e9e","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"a7c72e6432ad349baa44ec14362b8fbb552a1eadd8d972cc14548ffbf42d0e9e","first_computed_at":"2026-05-18T00:06:09.944176Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:06:09.944176Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"NREWNa3fFFUzV+nBmK2RlF/P3VH7lsxi4ae0F3SMowmAeD8Q0yeysFjQQjm6QvQqa6Q7JtNe6OAFw0pyx5gJCg==","signature_status":"signed_v1","signed_at":"2026-05-18T00:06:09.944900Z","signed_message":"canonical_sha256_bytes"},"source_id":"1809.03112","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:719a393b5dbe2d8d2d1ea7e87fc0af53d6d55395c5251e76f8cc1de990ba65e2","sha256:216104805ae61fb0c3665c608c76f2bc93c28376e5b7ff654123b7092bd15d56"],"state_sha256":"6e280bcbb033e8635707fca8ea33d58d78ad8701dc9d5da3820560586b2f813c"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"ophQBregsRN+r66mDWrLQMlVskR/Dkghec/s6qafaZhN+DAlAMJPtKkFcnFEFUMY2rOrsFgSZFkeEO1ddxFvAA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-28T13:36:57.562911Z","bundle_sha256":"321e6f00e350bf1a859487526540a3fb72d1b4e0ed90e6376de00b816a2d56ed"}}