{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2020:ERYKYOBXBHUPZEKKAEET4D7RAY","short_pith_number":"pith:ERYKYOBX","canonical_record":{"source":{"id":"2002.12327","kind":"arxiv","version":3},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CL","submitted_at":"2020-02-27T18:46:42Z","cross_cats_sorted":[],"title_canon_sha256":"369fb78ec1422c8a69815a5b848d643df7c2fc4f8271946a8183056d1d8a561e","abstract_canon_sha256":"0803aa87b4cc2c00fb5051cb9e48aa4f7d262f5877faa8d88184cf0519fd93e4"},"schema_version":"1.0"},"canonical_sha256":"2470ac383709e8fc914a01093e0ff1061e0d2a9659a68c267d5820d0f0f055ae","source":{"kind":"arxiv","id":"2002.12327","version":3},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2002.12327","created_at":"2026-07-05T01:50:11Z"},{"alias_kind":"arxiv_version","alias_value":"2002.12327v3","created_at":"2026-07-05T01:50:11Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2002.12327","created_at":"2026-07-05T01:50:11Z"},{"alias_kind":"pith_short_12","alias_value":"ERYKYOBXBHUP","created_at":"2026-07-05T01:50:11Z"},{"alias_kind":"pith_short_16","alias_value":"ERYKYOBXBHUPZEKK","created_at":"2026-07-05T01:50:11Z"},{"alias_kind":"pith_short_8","alias_value":"ERYKYOBX","created_at":"2026-07-05T01:50:11Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2020:ERYKYOBXBHUPZEKKAEET4D7RAY","target":"record","payload":{"canonical_record":{"source":{"id":"2002.12327","kind":"arxiv","version":3},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CL","submitted_at":"2020-02-27T18:46:42Z","cross_cats_sorted":[],"title_canon_sha256":"369fb78ec1422c8a69815a5b848d643df7c2fc4f8271946a8183056d1d8a561e","abstract_canon_sha256":"0803aa87b4cc2c00fb5051cb9e48aa4f7d262f5877faa8d88184cf0519fd93e4"},"schema_version":"1.0"},"canonical_sha256":"2470ac383709e8fc914a01093e0ff1061e0d2a9659a68c267d5820d0f0f055ae","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T01:50:11.423760Z","signature_b64":"KivnsKJIu8OC3oxMKF8+0I8ayBXpl0x+BtvgUGFcd3iCSR6ou69gx2lleoL0nFxnbQ2+XZlZM06XbulIyv+nAg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"2470ac383709e8fc914a01093e0ff1061e0d2a9659a68c267d5820d0f0f055ae","last_reissued_at":"2026-07-05T01:50:11.423339Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T01:50:11.423339Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2002.12327","source_version":3,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T01:50:11Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"Ze3oX4Sj+E+DuNDN6a6ZmBh8iLrj3ilWjT4lCdJZhyG+RonB37hwz7Pdnyz/Xw84UYQHpx2i1og65uErPGRGBQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-12T15:48:55.060136Z"},"content_sha256":"3a2f784bb95131658ad30125b0152f31ed10c69fc337b404bd0281e29be3634e","schema_version":"1.0","event_id":"sha256:3a2f784bb95131658ad30125b0152f31ed10c69fc337b404bd0281e29be3634e"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2020:ERYKYOBXBHUPZEKKAEET4D7RAY","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"A Primer in BERTology: What we know about how BERT works","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cs.CL","authors_text":"Anna Rogers, Anna Rumshisky, Olga Kovaleva","submitted_at":"2020-02-27T18:46:42Z","abstract_excerpt":"Transformer-based models have pushed state of the art in many areas of NLP, but our understanding of what is behind their success is still limited. This paper is the first survey of over 150 studies of the popular BERT model. We review the current state of knowledge about how BERT works, what kind of information it learns and how it is represented, common modifications to its training objectives and architecture, the overparameterization issue and approaches to compression. We then outline directions for future research."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2002.12327","kind":"arxiv","version":3},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2002.12327/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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":"2026-07-05T01:50:11Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"qYgeLdwXfuvpJ1R7eXwjvKvZo4SiqEW7y1BoQ2Iz7JuDh5FEoz017SvAWJeV9cDsxG2jfyedag1ZWtVPc1EKCg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-12T15:48:55.060635Z"},"content_sha256":"a6fbc4ca7633bf8f7c79861ecb9a5c2abad0edc572a948a2faacae024a147e17","schema_version":"1.0","event_id":"sha256:a6fbc4ca7633bf8f7c79861ecb9a5c2abad0edc572a948a2faacae024a147e17"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/ERYKYOBXBHUPZEKKAEET4D7RAY/bundle.json","state_url":"https://pith.science/pith/ERYKYOBXBHUPZEKKAEET4D7RAY/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/ERYKYOBXBHUPZEKKAEET4D7RAY/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":"2026-08-12T15:48:55Z","links":{"resolver":"https://pith.science/pith/ERYKYOBXBHUPZEKKAEET4D7RAY","bundle":"https://pith.science/pith/ERYKYOBXBHUPZEKKAEET4D7RAY/bundle.json","state":"https://pith.science/pith/ERYKYOBXBHUPZEKKAEET4D7RAY/state.json","well_known_bundle":"https://pith.science/.well-known/pith/ERYKYOBXBHUPZEKKAEET4D7RAY/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2020:ERYKYOBXBHUPZEKKAEET4D7RAY","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":"0803aa87b4cc2c00fb5051cb9e48aa4f7d262f5877faa8d88184cf0519fd93e4","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CL","submitted_at":"2020-02-27T18:46:42Z","title_canon_sha256":"369fb78ec1422c8a69815a5b848d643df7c2fc4f8271946a8183056d1d8a561e"},"schema_version":"1.0","source":{"id":"2002.12327","kind":"arxiv","version":3}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2002.12327","created_at":"2026-07-05T01:50:11Z"},{"alias_kind":"arxiv_version","alias_value":"2002.12327v3","created_at":"2026-07-05T01:50:11Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2002.12327","created_at":"2026-07-05T01:50:11Z"},{"alias_kind":"pith_short_12","alias_value":"ERYKYOBXBHUP","created_at":"2026-07-05T01:50:11Z"},{"alias_kind":"pith_short_16","alias_value":"ERYKYOBXBHUPZEKK","created_at":"2026-07-05T01:50:11Z"},{"alias_kind":"pith_short_8","alias_value":"ERYKYOBX","created_at":"2026-07-05T01:50:11Z"}],"graph_snapshots":[{"event_id":"sha256:a6fbc4ca7633bf8f7c79861ecb9a5c2abad0edc572a948a2faacae024a147e17","target":"graph","created_at":"2026-07-05T01:50:11Z","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"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/2002.12327/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"Transformer-based models have pushed state of the art in many areas of NLP, but our understanding of what is behind their success is still limited. This paper is the first survey of over 150 studies of the popular BERT model. We review the current state of knowledge about how BERT works, what kind of information it learns and how it is represented, common modifications to its training objectives and architecture, the overparameterization issue and approaches to compression. We then outline directions for future research.","authors_text":"Anna Rogers, Anna Rumshisky, Olga Kovaleva","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CL","submitted_at":"2020-02-27T18:46:42Z","title":"A Primer in BERTology: What we know about how BERT works"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2002.12327","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":"sha256:3a2f784bb95131658ad30125b0152f31ed10c69fc337b404bd0281e29be3634e","target":"record","created_at":"2026-07-05T01:50:11Z","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":"0803aa87b4cc2c00fb5051cb9e48aa4f7d262f5877faa8d88184cf0519fd93e4","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CL","submitted_at":"2020-02-27T18:46:42Z","title_canon_sha256":"369fb78ec1422c8a69815a5b848d643df7c2fc4f8271946a8183056d1d8a561e"},"schema_version":"1.0","source":{"id":"2002.12327","kind":"arxiv","version":3}},"canonical_sha256":"2470ac383709e8fc914a01093e0ff1061e0d2a9659a68c267d5820d0f0f055ae","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"2470ac383709e8fc914a01093e0ff1061e0d2a9659a68c267d5820d0f0f055ae","first_computed_at":"2026-07-05T01:50:11.423339Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T01:50:11.423339Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"KivnsKJIu8OC3oxMKF8+0I8ayBXpl0x+BtvgUGFcd3iCSR6ou69gx2lleoL0nFxnbQ2+XZlZM06XbulIyv+nAg==","signature_status":"signed_v1","signed_at":"2026-07-05T01:50:11.423760Z","signed_message":"canonical_sha256_bytes"},"source_id":"2002.12327","source_kind":"arxiv","source_version":3}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:3a2f784bb95131658ad30125b0152f31ed10c69fc337b404bd0281e29be3634e","sha256:a6fbc4ca7633bf8f7c79861ecb9a5c2abad0edc572a948a2faacae024a147e17"],"state_sha256":"03aa7f437324cf9f2fe3694cf7c126bf1c756593b997d199762a2ddd1ab94ed6"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"ILSYUOesOcfKFdywo3Bo+LF4fP728z9cLrypeiEmsCCN3t7BM1tneizmjjHFHIvVh+Wf5Sl1hB1BkzF2/3BCDA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-12T15:48:55.065391Z","bundle_sha256":"69468adb83e18568821c217e2bc02600c7940a75480922a9a3a4209266b91462"}}