21. ISO 80000-3 — Space and Time
The first part whose quantity-kinds and units are specified in full is ISO 80000-3, Space and time. Every item — all of 3-1.1 … 3-26.3 — is catalogued: length, the width/height/distance/radius family, area, volume, the angles, duration, the frequencies, velocity and speed, acceleration, the wave quantities, and the rest, each carrying its exact source as data: the part, the printed item designation, the principal quantity symbol, and the coherent SI unit symbol. Only citation locators are recorded; no normative content (definitions, remarks) from the licensed standard is reproduced. The defining mathematics of selected remarks is formalized in its own right, in the sibling modules linked below.
Part 3 turns out to be an unusually good proving ground for the calculus, because the standard itself is full of distinctions that a dimension-only or representation-only model cannot make: a dozen different length quantities, several dimensionless angles, and three families of quantities that share a dimension while remaining distinct kinds.
- 21.1. Quantity-kinds and units of ISO 80000-3
- 21.2. The length family: distinguishing kinds by measurement principle
- 21.3. Dimension does not classify; the kind does
- 21.4. Standard prefixes: the centimetre as centi · metre
- 21.5. Capturing a Remark's mathematics: the surface element of an area (item 3-3)
- 21.6. The volume element of a region (item 3-4)
- 21.7. The algebraic Remarks as kind-laws
- 21.8. Why it matters: classification and metrological consistency at the quantity level
- 21.9. Item index — ISO 80000-3