newRPL - build 1255 released! [updated to 1299]
07-31-2019, 06:07 PM
Post: #550
 JoJo1973 Member Posts: 106 Joined: Apr 2016
RE: newRPL - build 1255 released! [updated to 1282]
(07-31-2019 02:15 PM)Claudio L. Wrote:  EDIT: Actually, the operator | should have 3 different uses: enforcing rules, applying hints and providing constraints (equalities, inequalities, etc.), like 'X+Y+1 | X+Y>4'
I think inequalities can be handled with variable substitution:
A>B means A-B>0 (here A and B are arbitrary expressions, not variables), so we can substitute a=A-B (here 'a' is a variable) and therefore apply a rule A:→a+B
Then we can hint a:R>0 so the rules engine knows all the information the inequality provided.
Finally, after all is done (RULEAPPLY, AUTOSIMPLIFY, whatever), apply the inverse substitution: a:→A-B

Yes, the "given" operator fits perfectly the role. The issue of inequalities is an interesting one, especially for hyperbolic functions such as LN and EXP where constraining the argument about 1 rather than 0 is often seeked.
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