{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2016:MPTK2GGRAGKWXXNDBI4E6LIWSJ","short_pith_number":"pith:MPTK2GGR","canonical_record":{"source":{"id":"1602.05236","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"stat.ME","submitted_at":"2016-02-16T22:49:41Z","cross_cats_sorted":["stat.ML"],"title_canon_sha256":"4f4ce8e303cb2b2bc189a60d8c45807122dcbbf9c6021c5880211d294be74018","abstract_canon_sha256":"6d5c21b2809b4d6de2e65cf8955f88839df1eab721a860300f8db41731e7d0d3"},"schema_version":"1.0"},"canonical_sha256":"63e6ad18d101956bdda30a384f2d16926bbb96f0957fc43ecc0c8cb549b09639","source":{"kind":"arxiv","id":"1602.05236","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1602.05236","created_at":"2026-05-18T01:20:28Z"},{"alias_kind":"arxiv_version","alias_value":"1602.05236v1","created_at":"2026-05-18T01:20:28Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1602.05236","created_at":"2026-05-18T01:20:28Z"},{"alias_kind":"pith_short_12","alias_value":"MPTK2GGRAGKW","created_at":"2026-05-18T12:30:32Z"},{"alias_kind":"pith_short_16","alias_value":"MPTK2GGRAGKWXXND","created_at":"2026-05-18T12:30:32Z"},{"alias_kind":"pith_short_8","alias_value":"MPTK2GGR","created_at":"2026-05-18T12:30:32Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2016:MPTK2GGRAGKWXXNDBI4E6LIWSJ","target":"record","payload":{"canonical_record":{"source":{"id":"1602.05236","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"stat.ME","submitted_at":"2016-02-16T22:49:41Z","cross_cats_sorted":["stat.ML"],"title_canon_sha256":"4f4ce8e303cb2b2bc189a60d8c45807122dcbbf9c6021c5880211d294be74018","abstract_canon_sha256":"6d5c21b2809b4d6de2e65cf8955f88839df1eab721a860300f8db41731e7d0d3"},"schema_version":"1.0"},"canonical_sha256":"63e6ad18d101956bdda30a384f2d16926bbb96f0957fc43ecc0c8cb549b09639","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:20:28.809291Z","signature_b64":"mtnwyC+ey0IimDqTjgDa1e02qUUO+V0J3exFqS7DXKBx/l91Y2VkE95m+49aSfuD8FKTMtF4bY1tCD2UyVJsDg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"63e6ad18d101956bdda30a384f2d16926bbb96f0957fc43ecc0c8cb549b09639","last_reissued_at":"2026-05-18T01:20:28.808755Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:20:28.808755Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1602.05236","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":"2026-05-18T01:20:28Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"iOrHUv5gSrp1xFA6mPh3Y6fHIXcMHaIsm7CLLF7n6WRqaW2q5gfS49ZE9sJqVtkShZDgXhCTh0dtFw+MKC2ZAQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-07T17:52:53.072792Z"},"content_sha256":"1640bcf5597562252b66df22fab35ad18768a3c48772838b14d28d6fe03dadcd","schema_version":"1.0","event_id":"sha256:1640bcf5597562252b66df22fab35ad18768a3c48772838b14d28d6fe03dadcd"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2016:MPTK2GGRAGKWXXNDBI4E6LIWSJ","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"A Sparse PCA Approach to Clustering","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["stat.ML"],"primary_cat":"stat.ME","authors_text":"Linjun Zhang, T.Tony Cai","submitted_at":"2016-02-16T22:49:41Z","abstract_excerpt":"We discuss a clustering method for Gaussian mixture model based on the sparse principal component analysis (SPCA) method and compare it with the IF-PCA method. We also discuss the dependent case where the covariance matrix $\\Sigma$ is not necessarily diagonal."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1602.05236","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":"2026-05-18T01:20:28Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"KEhGVRLCjh/aMSBzRcI9FNX+XwX7LLnrItaDG0TdJzBwienIgYKFVBtnvmKBkAf0sfdig1nIpB7AeKtzgKImDA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-07T17:52:53.073555Z"},"content_sha256":"c13f762f7610d4f73aac30201e6d917bdd715ac18936f292391ba82929a08f76","schema_version":"1.0","event_id":"sha256:c13f762f7610d4f73aac30201e6d917bdd715ac18936f292391ba82929a08f76"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/MPTK2GGRAGKWXXNDBI4E6LIWSJ/bundle.json","state_url":"https://pith.science/pith/MPTK2GGRAGKWXXNDBI4E6LIWSJ/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/MPTK2GGRAGKWXXNDBI4E6LIWSJ/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":"2026-06-07T17:52:53Z","links":{"resolver":"https://pith.science/pith/MPTK2GGRAGKWXXNDBI4E6LIWSJ","bundle":"https://pith.science/pith/MPTK2GGRAGKWXXNDBI4E6LIWSJ/bundle.json","state":"https://pith.science/pith/MPTK2GGRAGKWXXNDBI4E6LIWSJ/state.json","well_known_bundle":"https://pith.science/.well-known/pith/MPTK2GGRAGKWXXNDBI4E6LIWSJ/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2016:MPTK2GGRAGKWXXNDBI4E6LIWSJ","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":"6d5c21b2809b4d6de2e65cf8955f88839df1eab721a860300f8db41731e7d0d3","cross_cats_sorted":["stat.ML"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"stat.ME","submitted_at":"2016-02-16T22:49:41Z","title_canon_sha256":"4f4ce8e303cb2b2bc189a60d8c45807122dcbbf9c6021c5880211d294be74018"},"schema_version":"1.0","source":{"id":"1602.05236","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1602.05236","created_at":"2026-05-18T01:20:28Z"},{"alias_kind":"arxiv_version","alias_value":"1602.05236v1","created_at":"2026-05-18T01:20:28Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1602.05236","created_at":"2026-05-18T01:20:28Z"},{"alias_kind":"pith_short_12","alias_value":"MPTK2GGRAGKW","created_at":"2026-05-18T12:30:32Z"},{"alias_kind":"pith_short_16","alias_value":"MPTK2GGRAGKWXXND","created_at":"2026-05-18T12:30:32Z"},{"alias_kind":"pith_short_8","alias_value":"MPTK2GGR","created_at":"2026-05-18T12:30:32Z"}],"graph_snapshots":[{"event_id":"sha256:c13f762f7610d4f73aac30201e6d917bdd715ac18936f292391ba82929a08f76","target":"graph","created_at":"2026-05-18T01:20:28Z","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":"We discuss a clustering method for Gaussian mixture model based on the sparse principal component analysis (SPCA) method and compare it with the IF-PCA method. We also discuss the dependent case where the covariance matrix $\\Sigma$ is not necessarily diagonal.","authors_text":"Linjun Zhang, T.Tony Cai","cross_cats":["stat.ML"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"stat.ME","submitted_at":"2016-02-16T22:49:41Z","title":"A Sparse PCA Approach to Clustering"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1602.05236","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":"sha256:1640bcf5597562252b66df22fab35ad18768a3c48772838b14d28d6fe03dadcd","target":"record","created_at":"2026-05-18T01:20:28Z","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":"6d5c21b2809b4d6de2e65cf8955f88839df1eab721a860300f8db41731e7d0d3","cross_cats_sorted":["stat.ML"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"stat.ME","submitted_at":"2016-02-16T22:49:41Z","title_canon_sha256":"4f4ce8e303cb2b2bc189a60d8c45807122dcbbf9c6021c5880211d294be74018"},"schema_version":"1.0","source":{"id":"1602.05236","kind":"arxiv","version":1}},"canonical_sha256":"63e6ad18d101956bdda30a384f2d16926bbb96f0957fc43ecc0c8cb549b09639","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"63e6ad18d101956bdda30a384f2d16926bbb96f0957fc43ecc0c8cb549b09639","first_computed_at":"2026-05-18T01:20:28.808755Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:20:28.808755Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"mtnwyC+ey0IimDqTjgDa1e02qUUO+V0J3exFqS7DXKBx/l91Y2VkE95m+49aSfuD8FKTMtF4bY1tCD2UyVJsDg==","signature_status":"signed_v1","signed_at":"2026-05-18T01:20:28.809291Z","signed_message":"canonical_sha256_bytes"},"source_id":"1602.05236","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:1640bcf5597562252b66df22fab35ad18768a3c48772838b14d28d6fe03dadcd","sha256:c13f762f7610d4f73aac30201e6d917bdd715ac18936f292391ba82929a08f76"],"state_sha256":"4c2f6a7a937e676808a4a549ab6965bc57401df7e83fb6df2689694d30aa9009"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"qpuEppTSqklTLHra2sygrLR0rG5JqAmg7iunoanOQ5E4W9C08cV6tYf+L8HAdACHA0MQFcj3raV/34n32DB3DQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-07T17:52:53.077479Z","bundle_sha256":"3a16597c0ea0c2339454526f7fe52538bdef9bd540dd1146ff1fba234755ba29"}}