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Source changed 2026-10-03 16:02:47 UTC · snapshot created 2026-10-03 16:03:51 UTC · last check 2026-10-03 16:25:20 UTC

A.6.6:5.1 - System archetype: calibration to a standard

Tell. A lab instrument channel TC‑17 is described as “anchored to ITS‑90”. Later, the reference standard is swapped, the phrase “still anchored” is kept, and the applicability window silently expands. Downstream work disagrees and nobody can reconstruct what changed.

Show. First state the direct assertion: TC-17 is calibrated to ITS-90 for rig R3 over 0–200 °C during the stated calibration interval. Apply the calibration predicate and stop there if this answers the use. When a later publication or comparison needs the exact assertion edition, show the same claim in an optional scoped record:

BD#Calib_TC17_v5 :=
〈 dependent    = ThermocoupleChannelRef(TC-17),
base         = StandardRef(ITS-90 / CalStd-2025-09),
directRelationKind = calibratedTo,
assertionPolarity  = affirmative,
scope        = WorkScope{rig=R3, range=[0..200]°C},
gammaTime          = interval[2025-09-01, 2026-03-01] 〉

When a later decision relies on this assertion, cite the exact A.2.4 evidence-use relation from the calibration-certificate episteme to the assertion. Use A.10 only if that decision also needs the producing Work, operation result, carrier, provenance, or currentness path. Then distinguish changes by what actually changed:

  • New standard ⇒ rebase + refreshWitnesses.
  • Wider applicability window ⇒ retime and likely refreshWitnesses.
  • Relation-kind change (“not calibration, just normalisation”) ⇒ changeDirectRelationKind is not an edit; mint a new assertion or declaration. Claim continuity with the prior episteme only when that history is needed and C.2.1:4.5’s rule and case facts establish it.