{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2026:KUGW6W2LTRZKJCPCSEFGGJ75XK","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":"9f1e391fa805a47078c66bd10ca1faeb5439a79aa601de9e79c3d6ded0e726c5","cross_cats_sorted":["cs.AI"],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"cs.LG","submitted_at":"2026-05-19T11:01:39Z","title_canon_sha256":"896b401ea71e2ff3164924a436283c1f19fa3f85d2c0f669a4c36d92d9dc858d"},"schema_version":"1.0","source":{"id":"2605.20296","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2605.20296","created_at":"2026-05-21T00:04:24Z"},{"alias_kind":"arxiv_version","alias_value":"2605.20296v1","created_at":"2026-05-21T00:04:24Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2605.20296","created_at":"2026-05-21T00:04:24Z"},{"alias_kind":"pith_short_12","alias_value":"KUGW6W2LTRZK","created_at":"2026-05-21T00:04:24Z"},{"alias_kind":"pith_short_16","alias_value":"KUGW6W2LTRZKJCPC","created_at":"2026-05-21T00:04:24Z"},{"alias_kind":"pith_short_8","alias_value":"KUGW6W2L","created_at":"2026-05-21T00:04:24Z"}],"graph_snapshots":[{"event_id":"sha256:22a881855c0ede60dfa6763e3459e88dac73d4061bdb9ad392365ce5220746f6","target":"graph","created_at":"2026-05-21T00:04:24Z","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/2605.20296/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"Fine-tuning a language model for a target task routinely degrades capabilities the training data never explicitly threatened. We study this phenomenon, known as catastrophic forgetting, and propose a post-hoc repair solution that uses only the pretrained checkpoint $W_{\\mathrm{base}}$ and its fine-tuned descendant $W_{\\mathrm{ft}}$. The goal is not merely to revert the model toward the base checkpoint, but to recover capabilities damaged by fine-tuning while preserving both the target-task gains and any beneficial held-out improvements. We introduce DG-Hard, a checkpoint-only spectral repair m","authors_text":"Aarash Abro, Muhammad Tahir","cross_cats":["cs.AI"],"headline":"","license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"cs.LG","submitted_at":"2026-05-19T11:01:39Z","title":"Spectral Unforgetting: Post-Hoc Recovery of Damaged Capabilities Without Retraining"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2605.20296","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":"sha256:337e09de6afb75393a4099dec2eb922d1fe77e65e8f8c5a36377559bddec3548","target":"record","created_at":"2026-05-21T00:04:24Z","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":"9f1e391fa805a47078c66bd10ca1faeb5439a79aa601de9e79c3d6ded0e726c5","cross_cats_sorted":["cs.AI"],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"cs.LG","submitted_at":"2026-05-19T11:01:39Z","title_canon_sha256":"896b401ea71e2ff3164924a436283c1f19fa3f85d2c0f669a4c36d92d9dc858d"},"schema_version":"1.0","source":{"id":"2605.20296","kind":"arxiv","version":1}},"canonical_sha256":"550d6f5b4b9c72a489e2910a6327fdba94256d4c3efcf018375ea3f675a76ff1","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"550d6f5b4b9c72a489e2910a6327fdba94256d4c3efcf018375ea3f675a76ff1","first_computed_at":"2026-05-21T00:04:24.381775Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-21T00:04:24.381775Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"9JrlI/VDqNGFjJ069AltOENNsb5utDSw3oFdD7UbojnoeGXlc67THqMcI+YEMehXlwI9hKBqTq7MAJZH2WKTAA==","signature_status":"signed_v1","signed_at":"2026-05-21T00:04:24.382197Z","signed_message":"canonical_sha256_bytes"},"source_id":"2605.20296","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:337e09de6afb75393a4099dec2eb922d1fe77e65e8f8c5a36377559bddec3548","sha256:22a881855c0ede60dfa6763e3459e88dac73d4061bdb9ad392365ce5220746f6"],"state_sha256":"160fa4d279986f241abcdac898d163d1e0c5899d404fee9be174110df9400606"}