{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2013:EIC4IUMQUZAGPHYFEFMWGWV6Q4","short_pith_number":"pith:EIC4IUMQ","canonical_record":{"source":{"id":"1305.2866","kind":"arxiv","version":4},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CG","submitted_at":"2013-05-13T17:31:48Z","cross_cats_sorted":["cs.CC"],"title_canon_sha256":"2700ba28d8c36519bb001fe466f4c91e8addce7036cd8fa4adbdfb4d261372c3","abstract_canon_sha256":"2163d5f8e3dd596e08cd9411bbd904fca7cabe76c058a950e53503d0d1adc255"},"schema_version":"1.0"},"canonical_sha256":"2205c45190a640679f052159635abe8725c2c1897992c364696f594cfd4536b8","source":{"kind":"arxiv","id":"1305.2866","version":4},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1305.2866","created_at":"2026-05-18T02:53:53Z"},{"alias_kind":"arxiv_version","alias_value":"1305.2866v4","created_at":"2026-05-18T02:53:53Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1305.2866","created_at":"2026-05-18T02:53:53Z"},{"alias_kind":"pith_short_12","alias_value":"EIC4IUMQUZAG","created_at":"2026-05-18T12:27:43Z"},{"alias_kind":"pith_short_16","alias_value":"EIC4IUMQUZAGPHYF","created_at":"2026-05-18T12:27:43Z"},{"alias_kind":"pith_short_8","alias_value":"EIC4IUMQ","created_at":"2026-05-18T12:27:43Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2013:EIC4IUMQUZAGPHYFEFMWGWV6Q4","target":"record","payload":{"canonical_record":{"source":{"id":"1305.2866","kind":"arxiv","version":4},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CG","submitted_at":"2013-05-13T17:31:48Z","cross_cats_sorted":["cs.CC"],"title_canon_sha256":"2700ba28d8c36519bb001fe466f4c91e8addce7036cd8fa4adbdfb4d261372c3","abstract_canon_sha256":"2163d5f8e3dd596e08cd9411bbd904fca7cabe76c058a950e53503d0d1adc255"},"schema_version":"1.0"},"canonical_sha256":"2205c45190a640679f052159635abe8725c2c1897992c364696f594cfd4536b8","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T02:53:53.838802Z","signature_b64":"XxTnTZLvfiGRUDpIfEBlmeex+czqAu1pwZ8lDmc1cMy0KNfA9YeauY38mWERfAEBjBJNMtkIaBaX9SODx60/Ag==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"2205c45190a640679f052159635abe8725c2c1897992c364696f594cfd4536b8","last_reissued_at":"2026-05-18T02:53:53.837903Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T02:53:53.837903Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1305.2866","source_version":4,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T02:53:53Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"1age5CeURQgYol0FY/ZTAJP1dPheHPCo0cbcgfLmT5QR8obJwr2p9xb7/blMsYdbbJhCie8yBvPXVMXG3stJDw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-07-03T07:09:02.006199Z"},"content_sha256":"b3fc3bf68c8cc5d7832080bff3a76f1439131ba3595fad52aa1b654400f9e474","schema_version":"1.0","event_id":"sha256:b3fc3bf68c8cc5d7832080bff3a76f1439131ba3595fad52aa1b654400f9e474"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2013:EIC4IUMQUZAGPHYFEFMWGWV6Q4","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Face-Guarding Polyhedra","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["cs.CC"],"primary_cat":"cs.CG","authors_text":"Giovanni Viglietta","submitted_at":"2013-05-13T17:31:48Z","abstract_excerpt":"We study the Art Gallery Problem for face guards in polyhedral environments. The problem can be informally stated as: how many (not necessarily convex) windows should we place on the external walls of a dark building, in order to completely illuminate its interior?\n  We consider both closed and open face guards (i.e., faces with or without their boundary), and we study several classes of polyhedra, including orthogonal polyhedra, 4-oriented polyhedra, and 2-reflex orthostacks.\n  We give upper and lower bounds on the minimum number of faces required to guard the interior of a given polyhedron i"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1305.2866","kind":"arxiv","version":4},"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":"2026-05-18T02:53:53Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"CBqOoZekZfrgDet63eECP/62SWylxJo1uuUV5X7ylwXW+rlPrqa3gTDKFiqp7SYysogOcFkOtzD+jM52RNumAA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-07-03T07:09:02.006544Z"},"content_sha256":"99326844ef683877d5740716230472649a78313fd00c9e45970653a8f59948bc","schema_version":"1.0","event_id":"sha256:99326844ef683877d5740716230472649a78313fd00c9e45970653a8f59948bc"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/EIC4IUMQUZAGPHYFEFMWGWV6Q4/bundle.json","state_url":"https://pith.science/pith/EIC4IUMQUZAGPHYFEFMWGWV6Q4/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/EIC4IUMQUZAGPHYFEFMWGWV6Q4/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":"2026-07-03T07:09:02Z","links":{"resolver":"https://pith.science/pith/EIC4IUMQUZAGPHYFEFMWGWV6Q4","bundle":"https://pith.science/pith/EIC4IUMQUZAGPHYFEFMWGWV6Q4/bundle.json","state":"https://pith.science/pith/EIC4IUMQUZAGPHYFEFMWGWV6Q4/state.json","well_known_bundle":"https://pith.science/.well-known/pith/EIC4IUMQUZAGPHYFEFMWGWV6Q4/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2013:EIC4IUMQUZAGPHYFEFMWGWV6Q4","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":"2163d5f8e3dd596e08cd9411bbd904fca7cabe76c058a950e53503d0d1adc255","cross_cats_sorted":["cs.CC"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CG","submitted_at":"2013-05-13T17:31:48Z","title_canon_sha256":"2700ba28d8c36519bb001fe466f4c91e8addce7036cd8fa4adbdfb4d261372c3"},"schema_version":"1.0","source":{"id":"1305.2866","kind":"arxiv","version":4}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1305.2866","created_at":"2026-05-18T02:53:53Z"},{"alias_kind":"arxiv_version","alias_value":"1305.2866v4","created_at":"2026-05-18T02:53:53Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1305.2866","created_at":"2026-05-18T02:53:53Z"},{"alias_kind":"pith_short_12","alias_value":"EIC4IUMQUZAG","created_at":"2026-05-18T12:27:43Z"},{"alias_kind":"pith_short_16","alias_value":"EIC4IUMQUZAGPHYF","created_at":"2026-05-18T12:27:43Z"},{"alias_kind":"pith_short_8","alias_value":"EIC4IUMQ","created_at":"2026-05-18T12:27:43Z"}],"graph_snapshots":[{"event_id":"sha256:99326844ef683877d5740716230472649a78313fd00c9e45970653a8f59948bc","target":"graph","created_at":"2026-05-18T02:53:53Z","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 study the Art Gallery Problem for face guards in polyhedral environments. The problem can be informally stated as: how many (not necessarily convex) windows should we place on the external walls of a dark building, in order to completely illuminate its interior?\n  We consider both closed and open face guards (i.e., faces with or without their boundary), and we study several classes of polyhedra, including orthogonal polyhedra, 4-oriented polyhedra, and 2-reflex orthostacks.\n  We give upper and lower bounds on the minimum number of faces required to guard the interior of a given polyhedron i","authors_text":"Giovanni Viglietta","cross_cats":["cs.CC"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CG","submitted_at":"2013-05-13T17:31:48Z","title":"Face-Guarding Polyhedra"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1305.2866","kind":"arxiv","version":4},"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:b3fc3bf68c8cc5d7832080bff3a76f1439131ba3595fad52aa1b654400f9e474","target":"record","created_at":"2026-05-18T02:53:53Z","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":"2163d5f8e3dd596e08cd9411bbd904fca7cabe76c058a950e53503d0d1adc255","cross_cats_sorted":["cs.CC"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CG","submitted_at":"2013-05-13T17:31:48Z","title_canon_sha256":"2700ba28d8c36519bb001fe466f4c91e8addce7036cd8fa4adbdfb4d261372c3"},"schema_version":"1.0","source":{"id":"1305.2866","kind":"arxiv","version":4}},"canonical_sha256":"2205c45190a640679f052159635abe8725c2c1897992c364696f594cfd4536b8","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"2205c45190a640679f052159635abe8725c2c1897992c364696f594cfd4536b8","first_computed_at":"2026-05-18T02:53:53.837903Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T02:53:53.837903Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"XxTnTZLvfiGRUDpIfEBlmeex+czqAu1pwZ8lDmc1cMy0KNfA9YeauY38mWERfAEBjBJNMtkIaBaX9SODx60/Ag==","signature_status":"signed_v1","signed_at":"2026-05-18T02:53:53.838802Z","signed_message":"canonical_sha256_bytes"},"source_id":"1305.2866","source_kind":"arxiv","source_version":4}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:b3fc3bf68c8cc5d7832080bff3a76f1439131ba3595fad52aa1b654400f9e474","sha256:99326844ef683877d5740716230472649a78313fd00c9e45970653a8f59948bc"],"state_sha256":"15a06299ddb34c85978c20262e93842c866c54c056d665357debe39913b84860"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"mphL6lRCprdQqu4tmsJqmGiYLVgFv2h72rzoqfLIR09xkW1tABG6/ZwyJec/wYpz1Lz4WQKR2gvdlR00Xh53Cw==","signed_message":"bundle_sha256_bytes","signed_at":"2026-07-03T07:09:02.008391Z","bundle_sha256":"5469f7f104d518496fd849fb9a98a7c5a65c22f919a6eabf8049494e6a0f6f0b"}}