James Davenport gave a talk on mathematical units in OpenMath.
New to me was the discussion on whether and when CDs/ units/ notations are obsolete (e.g. out-of-date)
- OpenMath CD is obsolete if the definition in it are for archival purposes only.
- A unit is obsolete by formal change (e.g. liter_pre1964) and by usage.
Or to distinguish relative and absolute temperatures … for addition “abs”+”rel”=”abs” (not arith1-plus?) …
Units are also very interesting in making mathematical expressions more intuitive and context-dependent. Maybe: A renderer converting from 1.2 miles (English) to (ca.) 1,92 km (German) should also convert the units and thus needs to provide basic computations (e.g. from miles to km)?