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Library / First Principles Framework (FPF) - Core Conceptual Specification
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Source changed 2026-10-03 11:52:20 UTC · snapshot created 2026-10-03 11:53:41 UTC · last check 2026-10-03 13:00:08 UTC

A.2.6:11.5 - Parallel support (SpanUnion) in a safety case

  • Line L1: tests on dry asphalt support braking property; scope S1={surface=dry, speed≤50 km/h}.
  • Line L2: simulations for wet asphalt; scope S2={surface=wet, speed≤40 km/h}.
  • Independence basis: partition P-braking identifies complete disjoint essential-component sets for this braking claim: L1 uses DryTrackTestRecord and DryRigCalibration; L2 uses WetBrakeModel, WetValidationRecord, and WetRigCalibration.
  • Published scope: SpanUnion({S1,S2}) = {(dry, ≤50), (wet, ≤40)}, with reference to P-braking.
  • Guard: allowed; union does not include (wet, 45) because not supported.

With only the method labels, leave P-UNION unresolved. If CalibrationRecord-Q is essential to both lines, P-UNION fails for this pair; retain the individual lines and use their component scopes to assess any dependent combination.