{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2020:VADJQWPFWCP2KNSV2C5M5NTRDM","short_pith_number":"pith:VADJQWPF","canonical_record":{"source":{"id":"2001.03788","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.DS","submitted_at":"2020-01-11T19:35:08Z","cross_cats_sorted":[],"title_canon_sha256":"664558881831fead1b898bbdd9da50259160c8010bcca8ebf7be0f669b4ecf15","abstract_canon_sha256":"f85a88e68e690ee33e83b51494fc585da3429bd61f4f417931bffdaeb4e8911a"},"schema_version":"1.0"},"canonical_sha256":"a8069859e5b09fa53655d0baceb6711b151d259b348c54543d21a55f221f9cc2","source":{"kind":"arxiv","id":"2001.03788","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2001.03788","created_at":"2026-07-05T00:32:55Z"},{"alias_kind":"arxiv_version","alias_value":"2001.03788v1","created_at":"2026-07-05T00:32:55Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2001.03788","created_at":"2026-07-05T00:32:55Z"},{"alias_kind":"pith_short_12","alias_value":"VADJQWPFWCP2","created_at":"2026-07-05T00:32:55Z"},{"alias_kind":"pith_short_16","alias_value":"VADJQWPFWCP2KNSV","created_at":"2026-07-05T00:32:55Z"},{"alias_kind":"pith_short_8","alias_value":"VADJQWPF","created_at":"2026-07-05T00:32:55Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2020:VADJQWPFWCP2KNSV2C5M5NTRDM","target":"record","payload":{"canonical_record":{"source":{"id":"2001.03788","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.DS","submitted_at":"2020-01-11T19:35:08Z","cross_cats_sorted":[],"title_canon_sha256":"664558881831fead1b898bbdd9da50259160c8010bcca8ebf7be0f669b4ecf15","abstract_canon_sha256":"f85a88e68e690ee33e83b51494fc585da3429bd61f4f417931bffdaeb4e8911a"},"schema_version":"1.0"},"canonical_sha256":"a8069859e5b09fa53655d0baceb6711b151d259b348c54543d21a55f221f9cc2","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T00:32:55.965184Z","signature_b64":"t9JLL8f971DhhKIO/JlMxlZ1TC/r3hY008lVL5I+q/Yv6xzz6CZ8rEqSRS6yC+hYV9rsUEQTd9zc1QREg7bNDQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"a8069859e5b09fa53655d0baceb6711b151d259b348c54543d21a55f221f9cc2","last_reissued_at":"2026-07-05T00:32:55.964777Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T00:32:55.964777Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2001.03788","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":"2026-07-05T00:32:55Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"LrjFh/Mo9nCEYbtdx1tLYhWyLbdm/MvvqmEXwXud1yzyB0o2Y93vfkoty/V7WsFnIYdRmY92A8tLEtu/OXfvCw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-15T05:31:11.177562Z"},"content_sha256":"89879a83677b0067f346eba3b4b38c6190491e9fde3bf560750cdfc60e7dc80f","schema_version":"1.0","event_id":"sha256:89879a83677b0067f346eba3b4b38c6190491e9fde3bf560750cdfc60e7dc80f"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2020:VADJQWPFWCP2KNSV2C5M5NTRDM","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Minimum $2$-vertex-twinless connected spanning subgraph problem","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cs.DS","authors_text":"Raed Jaberi","submitted_at":"2020-01-11T19:35:08Z","abstract_excerpt":"Given a $2$-vertex-twinless connected directed graph $G=(V,E)$, the minimum $2$-vertex-twinless connected spanning subgraph problem is to find a minimum cardinality edge subset $E^{t} \\subseteq E$ such that the subgraph $(V,E^{t})$ is $2$-vertex-twinless connected. Let $G^{1}$ be a minimal $2$-vertex-connected subgraph of $G$. In this paper we present a $(2+a_{t}/2)$-approximation algorithm for the minimum $2$-vertex-twinless connected spanning subgraph problem, where $a_{t}$ is the number of twinless articulation points in $G^{1}$."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2001.03788","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2001.03788/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":"2026-07-05T00:32:55Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"LbQNiEvTP71FPDVqjGe/eJS8RFp4s5BruIND789PctdTpTTQ/JZwWcDKXQkxW9mtFm+NEzm8ljQpQTZHrSoHCA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-15T05:31:11.178067Z"},"content_sha256":"79452aaa94f8b1f1dfe2e3fe7304964fa7999b2a43a0e6f20a61d307c3c50935","schema_version":"1.0","event_id":"sha256:79452aaa94f8b1f1dfe2e3fe7304964fa7999b2a43a0e6f20a61d307c3c50935"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/VADJQWPFWCP2KNSV2C5M5NTRDM/bundle.json","state_url":"https://pith.science/pith/VADJQWPFWCP2KNSV2C5M5NTRDM/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/VADJQWPFWCP2KNSV2C5M5NTRDM/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":"2026-08-15T05:31:11Z","links":{"resolver":"https://pith.science/pith/VADJQWPFWCP2KNSV2C5M5NTRDM","bundle":"https://pith.science/pith/VADJQWPFWCP2KNSV2C5M5NTRDM/bundle.json","state":"https://pith.science/pith/VADJQWPFWCP2KNSV2C5M5NTRDM/state.json","well_known_bundle":"https://pith.science/.well-known/pith/VADJQWPFWCP2KNSV2C5M5NTRDM/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2020:VADJQWPFWCP2KNSV2C5M5NTRDM","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":"f85a88e68e690ee33e83b51494fc585da3429bd61f4f417931bffdaeb4e8911a","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.DS","submitted_at":"2020-01-11T19:35:08Z","title_canon_sha256":"664558881831fead1b898bbdd9da50259160c8010bcca8ebf7be0f669b4ecf15"},"schema_version":"1.0","source":{"id":"2001.03788","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2001.03788","created_at":"2026-07-05T00:32:55Z"},{"alias_kind":"arxiv_version","alias_value":"2001.03788v1","created_at":"2026-07-05T00:32:55Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2001.03788","created_at":"2026-07-05T00:32:55Z"},{"alias_kind":"pith_short_12","alias_value":"VADJQWPFWCP2","created_at":"2026-07-05T00:32:55Z"},{"alias_kind":"pith_short_16","alias_value":"VADJQWPFWCP2KNSV","created_at":"2026-07-05T00:32:55Z"},{"alias_kind":"pith_short_8","alias_value":"VADJQWPF","created_at":"2026-07-05T00:32:55Z"}],"graph_snapshots":[{"event_id":"sha256:79452aaa94f8b1f1dfe2e3fe7304964fa7999b2a43a0e6f20a61d307c3c50935","target":"graph","created_at":"2026-07-05T00:32:55Z","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/2001.03788/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"Given a $2$-vertex-twinless connected directed graph $G=(V,E)$, the minimum $2$-vertex-twinless connected spanning subgraph problem is to find a minimum cardinality edge subset $E^{t} \\subseteq E$ such that the subgraph $(V,E^{t})$ is $2$-vertex-twinless connected. Let $G^{1}$ be a minimal $2$-vertex-connected subgraph of $G$. In this paper we present a $(2+a_{t}/2)$-approximation algorithm for the minimum $2$-vertex-twinless connected spanning subgraph problem, where $a_{t}$ is the number of twinless articulation points in $G^{1}$.","authors_text":"Raed Jaberi","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.DS","submitted_at":"2020-01-11T19:35:08Z","title":"Minimum $2$-vertex-twinless connected spanning subgraph problem"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2001.03788","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":"sha256:89879a83677b0067f346eba3b4b38c6190491e9fde3bf560750cdfc60e7dc80f","target":"record","created_at":"2026-07-05T00:32:55Z","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":"f85a88e68e690ee33e83b51494fc585da3429bd61f4f417931bffdaeb4e8911a","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.DS","submitted_at":"2020-01-11T19:35:08Z","title_canon_sha256":"664558881831fead1b898bbdd9da50259160c8010bcca8ebf7be0f669b4ecf15"},"schema_version":"1.0","source":{"id":"2001.03788","kind":"arxiv","version":1}},"canonical_sha256":"a8069859e5b09fa53655d0baceb6711b151d259b348c54543d21a55f221f9cc2","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"a8069859e5b09fa53655d0baceb6711b151d259b348c54543d21a55f221f9cc2","first_computed_at":"2026-07-05T00:32:55.964777Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T00:32:55.964777Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"t9JLL8f971DhhKIO/JlMxlZ1TC/r3hY008lVL5I+q/Yv6xzz6CZ8rEqSRS6yC+hYV9rsUEQTd9zc1QREg7bNDQ==","signature_status":"signed_v1","signed_at":"2026-07-05T00:32:55.965184Z","signed_message":"canonical_sha256_bytes"},"source_id":"2001.03788","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:89879a83677b0067f346eba3b4b38c6190491e9fde3bf560750cdfc60e7dc80f","sha256:79452aaa94f8b1f1dfe2e3fe7304964fa7999b2a43a0e6f20a61d307c3c50935"],"state_sha256":"3679f2394a748bd320bb28f9992cf8d780e28e125aeede342238d54a2f4cfdac"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"r0xRkvhqf6ueIVhnAqlH63GMjmCx7vyHcIedbLiCahI4bNa0/HqDthZBGehVl3Gi9BOfyCEraC/sQBuo55ieDg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-15T05:31:11.181845Z","bundle_sha256":"176c8bb6ab5a86c4f66309289055029a671ad255a1e278a1425d1ae30c7956e1"}}