{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2014:3TABJ7ODRKC7V24N52OS4DSEMK","short_pith_number":"pith:3TABJ7OD","canonical_record":{"source":{"id":"1408.5965","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.FL","submitted_at":"2014-08-26T01:16:15Z","cross_cats_sorted":[],"title_canon_sha256":"6c55115d6ab43563e1869a7822f3612f0a19ed7e07cc65dbf53263be157fc0ab","abstract_canon_sha256":"738473dde2e8253b70e7c7ce9114659b2ad07cb0391e635d42cd01a861527534"},"schema_version":"1.0"},"canonical_sha256":"dcc014fdc38a85faeb8dee9d2e0e44628a07735daa243c43b20e00226e410370","source":{"kind":"arxiv","id":"1408.5965","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1408.5965","created_at":"2026-05-18T02:44:15Z"},{"alias_kind":"arxiv_version","alias_value":"1408.5965v1","created_at":"2026-05-18T02:44:15Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1408.5965","created_at":"2026-05-18T02:44:15Z"},{"alias_kind":"pith_short_12","alias_value":"3TABJ7ODRKC7","created_at":"2026-05-18T12:28:11Z"},{"alias_kind":"pith_short_16","alias_value":"3TABJ7ODRKC7V24N","created_at":"2026-05-18T12:28:11Z"},{"alias_kind":"pith_short_8","alias_value":"3TABJ7OD","created_at":"2026-05-18T12:28:11Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2014:3TABJ7ODRKC7V24N52OS4DSEMK","target":"record","payload":{"canonical_record":{"source":{"id":"1408.5965","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.FL","submitted_at":"2014-08-26T01:16:15Z","cross_cats_sorted":[],"title_canon_sha256":"6c55115d6ab43563e1869a7822f3612f0a19ed7e07cc65dbf53263be157fc0ab","abstract_canon_sha256":"738473dde2e8253b70e7c7ce9114659b2ad07cb0391e635d42cd01a861527534"},"schema_version":"1.0"},"canonical_sha256":"dcc014fdc38a85faeb8dee9d2e0e44628a07735daa243c43b20e00226e410370","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T02:44:15.611525Z","signature_b64":"TFx9zbQM7cOk3FYp1Pqz4JOC0yrRLFPo51rLhfamH+94A035jbwTR56t/B0lwTqGzAgapedehYajmx0Ssk7gCw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"dcc014fdc38a85faeb8dee9d2e0e44628a07735daa243c43b20e00226e410370","last_reissued_at":"2026-05-18T02:44:15.611062Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T02:44:15.611062Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1408.5965","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":"2026-05-18T02:44:15Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"YG4A3TV97HluDBlrawIlyaHGhkycvQDVJ51DvZvFAScipCi3HPLyZyGRVn3inv9BnhWhk0PkcsJWHSvqg+jWAA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-26T15:16:43.550380Z"},"content_sha256":"78e15f946883c0f110ad7f2752eac91a634b6d1fc99fba30ac1fce45eb0c59a9","schema_version":"1.0","event_id":"sha256:78e15f946883c0f110ad7f2752eac91a634b6d1fc99fba30ac1fce45eb0c59a9"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2014:3TABJ7ODRKC7V24N52OS4DSEMK","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Hourglass Automata","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cs.FL","authors_text":"Harry Smallbone (The University of Western Australia), Mark Reynolds (The University of Western Australia), Tim French (The University of Western Australia), Yuki Osada (The University of Western Australia)","submitted_at":"2014-08-26T01:16:15Z","abstract_excerpt":"In this paper, we define the class of hourglass automata, which are timed automata with bounded clocks that can be made to progress backwards as well as forwards at a constant rate. We then introduce a new clock update for timed automata that allows hourglass automata to be expressed. This allows us to show that language emptiness remains decidable with this update when the number of clocks is two or less. This is done by showing that we can construct a finite untimed graph using clock regions from any timed automaton that use this new update."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1408.5965","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":"2026-05-18T02:44:15Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"vL8WIhuizWnR15ox63xzS5xt8eSMQ+Q4DS9DWkOKUf6OyoKqFXMCEGB/Xv4CDWLbpMHfMC01/XgvKnfFvrz+AQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-26T15:16:43.550737Z"},"content_sha256":"b8b06f4e6551aca5f54ed0061fe152ec356b7a1a4b82607e25b440bbc32e7314","schema_version":"1.0","event_id":"sha256:b8b06f4e6551aca5f54ed0061fe152ec356b7a1a4b82607e25b440bbc32e7314"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/3TABJ7ODRKC7V24N52OS4DSEMK/bundle.json","state_url":"https://pith.science/pith/3TABJ7ODRKC7V24N52OS4DSEMK/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/3TABJ7ODRKC7V24N52OS4DSEMK/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":"2026-06-26T15:16:43Z","links":{"resolver":"https://pith.science/pith/3TABJ7ODRKC7V24N52OS4DSEMK","bundle":"https://pith.science/pith/3TABJ7ODRKC7V24N52OS4DSEMK/bundle.json","state":"https://pith.science/pith/3TABJ7ODRKC7V24N52OS4DSEMK/state.json","well_known_bundle":"https://pith.science/.well-known/pith/3TABJ7ODRKC7V24N52OS4DSEMK/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2014:3TABJ7ODRKC7V24N52OS4DSEMK","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":"738473dde2e8253b70e7c7ce9114659b2ad07cb0391e635d42cd01a861527534","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.FL","submitted_at":"2014-08-26T01:16:15Z","title_canon_sha256":"6c55115d6ab43563e1869a7822f3612f0a19ed7e07cc65dbf53263be157fc0ab"},"schema_version":"1.0","source":{"id":"1408.5965","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1408.5965","created_at":"2026-05-18T02:44:15Z"},{"alias_kind":"arxiv_version","alias_value":"1408.5965v1","created_at":"2026-05-18T02:44:15Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1408.5965","created_at":"2026-05-18T02:44:15Z"},{"alias_kind":"pith_short_12","alias_value":"3TABJ7ODRKC7","created_at":"2026-05-18T12:28:11Z"},{"alias_kind":"pith_short_16","alias_value":"3TABJ7ODRKC7V24N","created_at":"2026-05-18T12:28:11Z"},{"alias_kind":"pith_short_8","alias_value":"3TABJ7OD","created_at":"2026-05-18T12:28:11Z"}],"graph_snapshots":[{"event_id":"sha256:b8b06f4e6551aca5f54ed0061fe152ec356b7a1a4b82607e25b440bbc32e7314","target":"graph","created_at":"2026-05-18T02:44:15Z","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":"In this paper, we define the class of hourglass automata, which are timed automata with bounded clocks that can be made to progress backwards as well as forwards at a constant rate. We then introduce a new clock update for timed automata that allows hourglass automata to be expressed. This allows us to show that language emptiness remains decidable with this update when the number of clocks is two or less. This is done by showing that we can construct a finite untimed graph using clock regions from any timed automaton that use this new update.","authors_text":"Harry Smallbone (The University of Western Australia), Mark Reynolds (The University of Western Australia), Tim French (The University of Western Australia), Yuki Osada (The University of Western Australia)","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.FL","submitted_at":"2014-08-26T01:16:15Z","title":"Hourglass Automata"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1408.5965","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":"sha256:78e15f946883c0f110ad7f2752eac91a634b6d1fc99fba30ac1fce45eb0c59a9","target":"record","created_at":"2026-05-18T02:44:15Z","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":"738473dde2e8253b70e7c7ce9114659b2ad07cb0391e635d42cd01a861527534","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.FL","submitted_at":"2014-08-26T01:16:15Z","title_canon_sha256":"6c55115d6ab43563e1869a7822f3612f0a19ed7e07cc65dbf53263be157fc0ab"},"schema_version":"1.0","source":{"id":"1408.5965","kind":"arxiv","version":1}},"canonical_sha256":"dcc014fdc38a85faeb8dee9d2e0e44628a07735daa243c43b20e00226e410370","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"dcc014fdc38a85faeb8dee9d2e0e44628a07735daa243c43b20e00226e410370","first_computed_at":"2026-05-18T02:44:15.611062Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T02:44:15.611062Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"TFx9zbQM7cOk3FYp1Pqz4JOC0yrRLFPo51rLhfamH+94A035jbwTR56t/B0lwTqGzAgapedehYajmx0Ssk7gCw==","signature_status":"signed_v1","signed_at":"2026-05-18T02:44:15.611525Z","signed_message":"canonical_sha256_bytes"},"source_id":"1408.5965","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:78e15f946883c0f110ad7f2752eac91a634b6d1fc99fba30ac1fce45eb0c59a9","sha256:b8b06f4e6551aca5f54ed0061fe152ec356b7a1a4b82607e25b440bbc32e7314"],"state_sha256":"d999d7453ed10ff1a9c104e560f35034be5d3af0e949c45adc549b1dcfe12b56"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"5q86Ha+t8pgRfiyWicFkoplpVzigUQMWLkx7YZxOZCrJD9+aPRnTG3xI75ifzX15UH2iAI6xc6txoXQDSVnGCQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-26T15:16:43.552762Z","bundle_sha256":"ff714f71f6c3a7a7aec379957e5c3257ad8ca0130d3726c9074bcb2491148d7f"}}