Does anyone know if this was the system used by higher end TI calculators like the TI-92? It had a 'rational' mode for exact answers and I suspect that it used RRA for that.
The TI-92 and similar have a full-on computer algebra system that they use when they're in exact mode [1]. It does symbolic manipulation.
This is different from what the post (and linked paper) discuss, where the result will degrade to recursive real arithmetic, which is correct but only to a bounded level of precision. A CAS will always give a fully-exact (although sometimes very unwieldy) answer.
