{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2017:UW5EOGSFSBD6OFNNJM2UMUX2NV","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":"dee944d9da662a912ca81f9d367a19c697981f1b665b4e95c3e8a8bafcacb08b","cross_cats_sorted":["math.IT"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2017-07-05T16:14:44Z","title_canon_sha256":"b9f8c709e20e734c8f8083ee056966b71ba501d955038c1adde13fa750edf10c"},"schema_version":"1.0","source":{"id":"1707.01451","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1707.01451","created_at":"2026-05-18T00:33:16Z"},{"alias_kind":"arxiv_version","alias_value":"1707.01451v1","created_at":"2026-05-18T00:33:16Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1707.01451","created_at":"2026-05-18T00:33:16Z"},{"alias_kind":"pith_short_12","alias_value":"UW5EOGSFSBD6","created_at":"2026-05-18T12:31:49Z"},{"alias_kind":"pith_short_16","alias_value":"UW5EOGSFSBD6OFNN","created_at":"2026-05-18T12:31:49Z"},{"alias_kind":"pith_short_8","alias_value":"UW5EOGSF","created_at":"2026-05-18T12:31:49Z"}],"graph_snapshots":[{"event_id":"sha256:31a99df022bbaabd2bada3bbf69ba03c9ab1c8eedabe4965e114138b2268ad37","target":"graph","created_at":"2026-05-18T00:33:16Z","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 complex-valued signal is improper if it is correlated with its complex conjugate. The dimension of the improper signal subspace, i.e., the number of improper components in a complex-valued measurement, is an important parameter and is unknown in most applications. In this letter, we introduce two approaches to estimate this dimension, one based on an information- theoretic criterion and one based on hypothesis testing. We also present reduced-rank versions of these approaches that work for scenarios where the number of observations is comparable to or even smaller than the dimension of the d","authors_text":"Christian Lameiro, Peter J. Schreier, Tanuj Hasija","cross_cats":["math.IT"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2017-07-05T16:14:44Z","title":"Determining the Dimension of the Improper Signal Subspace in Complex-Valued Data"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1707.01451","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":"sha256:89a24555f926d0e5c0ae9c158241219a3ada1f87593ac6dcc4a9b3b468fdaf2b","target":"record","created_at":"2026-05-18T00:33:16Z","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":"dee944d9da662a912ca81f9d367a19c697981f1b665b4e95c3e8a8bafcacb08b","cross_cats_sorted":["math.IT"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.IT","submitted_at":"2017-07-05T16:14:44Z","title_canon_sha256":"b9f8c709e20e734c8f8083ee056966b71ba501d955038c1adde13fa750edf10c"},"schema_version":"1.0","source":{"id":"1707.01451","kind":"arxiv","version":1}},"canonical_sha256":"a5ba471a459047e715ad4b354652fa6d43768b91afd1b3466a4f5c7a45f52a0a","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"a5ba471a459047e715ad4b354652fa6d43768b91afd1b3466a4f5c7a45f52a0a","first_computed_at":"2026-05-18T00:33:16.683800Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:33:16.683800Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"4zHpoeAjA+fTTC8BqJj+H6KeD+ZX/SYHzTbICj4oqZKXeg7f5snBnxqqhnEHOTqc0IZ7/lJQT2Na3mlxc4WaBQ==","signature_status":"signed_v1","signed_at":"2026-05-18T00:33:16.684416Z","signed_message":"canonical_sha256_bytes"},"source_id":"1707.01451","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:89a24555f926d0e5c0ae9c158241219a3ada1f87593ac6dcc4a9b3b468fdaf2b","sha256:31a99df022bbaabd2bada3bbf69ba03c9ab1c8eedabe4965e114138b2268ad37"],"state_sha256":"8593015cc2c72d5483b8628bd90abdbeb0a1262344e008f5a504355faffc8862"}