{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2019:NXBOJZDFNJYEUCNO6RTIXA3OEW","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":"b2adcae5722f3485ae35b347d7ed2ab467c21411aa7c292b82ce5d3721f9b858","cross_cats_sorted":["stat.CO"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"stat.ME","submitted_at":"2019-07-10T11:16:05Z","title_canon_sha256":"5a17f48a9314bdca8abffe9a79e6d8b184a1b66c4674a0a67b9e92c29f7478b6"},"schema_version":"1.0","source":{"id":"1907.04620","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1907.04620","created_at":"2026-05-17T23:40:57Z"},{"alias_kind":"arxiv_version","alias_value":"1907.04620v1","created_at":"2026-05-17T23:40:57Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1907.04620","created_at":"2026-05-17T23:40:57Z"},{"alias_kind":"pith_short_12","alias_value":"NXBOJZDFNJYE","created_at":"2026-05-18T12:33:24Z"},{"alias_kind":"pith_short_16","alias_value":"NXBOJZDFNJYEUCNO","created_at":"2026-05-18T12:33:24Z"},{"alias_kind":"pith_short_8","alias_value":"NXBOJZDF","created_at":"2026-05-18T12:33:24Z"}],"graph_snapshots":[{"event_id":"sha256:a4d5370a708f3627e90ea776d88d87814d741bd60243b3dcdafebcd38fdf68fc","target":"graph","created_at":"2026-05-17T23:40:57Z","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":"This paper considers sparsity in linear regression under the restriction that the regression weights sum to one. We propose an approach that combines $\\ell_0$- and $\\ell_1$-regularization. We compute its solution by adapting a recent methodological innovation made by Bertsimas et al. (2016) for $\\ell_0$-regularization in standard linear regression. In a simulation experiment we compare our approach to $\\ell_0$-regularization and $\\ell_1$-regularization and find that it performs favorably in terms of predictive performance and sparsity. In an application to index tracking we show that our appro","authors_text":"Nick Koning, Paul Bekker","cross_cats":["stat.CO"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"stat.ME","submitted_at":"2019-07-10T11:16:05Z","title":"Sparse Unit-Sum Regression"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1907.04620","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:b9a32d105a2ba5fa7e00db5ef46ffb8ae4ef67a96b29c977513d9b9cfc0f67f4","target":"record","created_at":"2026-05-17T23:40:57Z","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":"b2adcae5722f3485ae35b347d7ed2ab467c21411aa7c292b82ce5d3721f9b858","cross_cats_sorted":["stat.CO"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"stat.ME","submitted_at":"2019-07-10T11:16:05Z","title_canon_sha256":"5a17f48a9314bdca8abffe9a79e6d8b184a1b66c4674a0a67b9e92c29f7478b6"},"schema_version":"1.0","source":{"id":"1907.04620","kind":"arxiv","version":1}},"canonical_sha256":"6dc2e4e4656a704a09aef4668b836e25a428c1dd5dc54b29c29afdd84d49c29b","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"6dc2e4e4656a704a09aef4668b836e25a428c1dd5dc54b29c29afdd84d49c29b","first_computed_at":"2026-05-17T23:40:57.343456Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-17T23:40:57.343456Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"Qysu+tCekVC1dYr3EjIYcn3Nmhkep88G2Iafc9DjkaLetHzIpyfY3Xlo6i9IpJBMox0IHv7KGVZTSR31jg/GAQ==","signature_status":"signed_v1","signed_at":"2026-05-17T23:40:57.344095Z","signed_message":"canonical_sha256_bytes"},"source_id":"1907.04620","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:b9a32d105a2ba5fa7e00db5ef46ffb8ae4ef67a96b29c977513d9b9cfc0f67f4","sha256:a4d5370a708f3627e90ea776d88d87814d741bd60243b3dcdafebcd38fdf68fc"],"state_sha256":"b6aca729205be2ffdb797f1d5d4c38009087252e909bc83f1426e1d866f4a821"}