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The lost book is a row of shared digits
Status is derived only from the shepherd-authored triage/prediction data above -- community submissions and claims are a separate overlay and can never change it (see the participation panel below).
Claim (verbatim)
Āryabhaṭa (born 476) wrote two astronomies: the Āryabhaṭīya, which survives, reckoning the day from sunrise, and a second system reckoning from midnight — the ārdharātrika system, the so-called Āryabhaṭasiddhānta — which is lost. Its afterlife is purely parametric: Brahmagupta built his working handbook, the Khaṇḍakhādyaka (665), expressly on Āryabhaṭa's midnight system, and Bhāskara I's Mahābhāskarīya devotes a chapter to reporting the midnight system's constants alongside the sunrise system's. A lost siddhānta reduced to numbers in other men's books is recoverable exactly insofar as the numbers were fixed: if one written text stood behind both witnesses, the parameter vectors they transmit must agree digit for digit; if "the midnight system" was a school habit rather than a book, the reports should drift the way remembered numbers drift. K. S. Shukla assembled the ārdharātrika testimonia half a century ago; the two-channel comparison is a table anyone can build from published editions, and it decides whether this ghost was a text or a rumour. Prediction: tabulating every parameter of the midnight system independently recoverable from the Khaṇḍakhādyaka and from the Mahābhāskarīya's account — revolution numbers in a yuga, civil-day counts, epicycle circumferences, apogee and node positions — at least 90% of the shared parameters will agree exactly, digit for digit, across the two channels, fixing a single written source behind both (primary clause: the 90% exact-agreement floor; systematic divergence in the core revolution numbers kills it). Kill: the Khaṇḍakhādyaka editions of P. C. Sengupta (Calcutta, 1934) and Bina Chatterjee (New Delhi, 1970), K. S. Shukla's edition of the Mahābhāskarīya (Lucknow, 1960) and his study "Āryabhaṭa I's astronomy with midnight day-reckoning" (Gaṇita 18, 1967), controlled against David Pingree's Census of the Exact Sciences in Sanskrit, s.v. Āryabhaṭa.
Prediction clause (verbatim)
Prediction: tabulating every parameter of the midnight system independently recoverable from the Khaṇḍakhādyaka and from the Mahābhāskarīya's account — revolution numbers in a yuga, civil-day counts, epicycle circumferences, apogee and node positions — at least 90% of the shared parameters will agree exactly, digit for digit, across the two channels, fixing a single written source behind both (primary clause: the 90% exact-agreement floor; systematic divergence in the core revolution numbers kills it).
Kill-dataset (verbatim)
Kill: the Khaṇḍakhādyaka editions of P. C. Sengupta (Calcutta, 1934) and Bina Chatterjee (New Delhi, 1970), K. S. Shukla's edition of the Mahābhāskarīya (Lucknow, 1960) and his study "Āryabhaṭa I's astronomy with midnight day-reckoning" (Gaṇita 18, 1967), controlled against David Pingree's Census of the Exact Sciences in Sanskrit, s.v. Āryabhaṭa.
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How this item is catalogued
Catalogue tags are curatorial metadata that make the conjecture findable. They are not findings, not a novelty verdict, and naming a source family is not a promise that the data exist or are accessible. Each dimension below says whether it was assigned, reviewed with none applying, uncertain, or not yet reviewed, and who recorded it.
- Place & era tags — Assigned
- South Asia; Medieval Tagged by Claude (Opus 4.8)
- Dating — Phenomenon
- Dated c. 470 CE – 670 CE Aryabhata's (b.476) lost ardharatrika astronomical system, attested via Brahmagupta's Khandakhadyaka (665) and Bhaskara I's Mahabhaskariya (c.629); Shukla's/Sengupta's editions are the instrument. Tagged by claude-sonnet-5 + claude-fable-5 (gate)
- Subject — Assigned
- Time, sky & calendars; Texts, scribes & transmission a lost astronomical system recoverable only via numeric constants embedded in later handbooks Tagged by claude-sonnet-5
- Finer subject topic — Assigned
- Lost books a lost siddhanta recoverable only as numbers embedded in other men's books Tagged by claude-opus-5 draft (requested max effort) adjudicated by claude-fable-5-1 driver, lane 1da5; runtime not independently attested
- Claim level — Assigned
- Record claim the prediction tests whether two later handbooks transmit one written source's parameters digit for digit, a transmission-fidelity claim Tagged by claude-opus-5 draft (requested max effort) adjudicated by claude-fable-5-1 driver, lane 1da5; runtime not independently attested
- Method — Reviewed — none applies
- the registered statistic is a 90 percent exact digit-for-digit agreement share across the parameters recoverable from the two texts; no opposite-signature channel comparison, no error spectrum and no stemma from shared error Tagged by claude-opus-5 draft (requested max effort) adjudicated by claude-fable-5-1 driver, lane 1da5; runtime not independently attested
- Evidence source — Assigned
- Astronomical tables; Published editions the test tabulates revolution numbers, epicycles and apogees from the Khandakhadyaka and Mahabhaskariya editions, the astronomical-parameter family, controlled against Pingree's Census Tagged by claude-opus-5 draft (requested max effort) adjudicated by claude-fable-5-1 driver, lane 1da5; runtime not independently attested
- Research stage — Idea — no test designed
On Inferpedia
This conjecture is linked to the following pages on Inferpedia, an encyclopedia of the missing — working atlas pages, some still early scaffolding.
Provenance
Run: Fresh agent generation · model: claude-fable-5
Fresh blind generation by claude-fable-5, 2026-07-17, India/South Asia wave 2 weighted by inferred textual production rather than survival; every item grounded in real works, authors, catalogues, and testimonia, including the real evidence of loss (citing authors, sole codices, translation corpora, epigraphic attestation, editio-princeps histories); no fabricated citations; deliberately occupying ground disjoint from the 2026-07-16 India wave and the earlier w14 South Asia wave.
Novelty / leakage triage
already answered in the literature
Shukla assembled the ardharatrika testimonia and reconstructed the midnight system precisely from the agreement of the two channels, and the standard accounts state that nearly all the system's constants are shared between the Khandakhadyaka and the Mahabhaskariya's report - the digit-level agreement fixing a single written source is the published basis of the reconstruction, with only the 90% bookkeeping left.
Sources cited by the triage
- K.S. Shukla, 'Aryabhata I's astronomy with midnight day-reckoning', Ganita 18 (1967)
- B. Chatterjee (ed.), The Khandakhadyaka of Brahmagupta (New Delhi, 1970), introduction and parameter tables
Predictions
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