[R] set package: more information about syntax

Jarek Jasiewicz jarekj at amu.edu.pl
Thu Oct 1 15:56:21 CEST 2009

> Dear All!
> I have a few question about proper syntax for fuzzy rules in sets 
> package (there is only little help about it):
> 1) how to use negation (NOT) operator there is only OR (||) in example 
> it is NOT, !!, !. I also assume that AND is &&
> 2) where it can be set. For example:
> area %is NOT% large
> area %is% NOT large
> area %is% !large
> etc...
> 3) how brackets works (as in typical logical operation, are allowed - 
> some expert system do not allow use brackets)
> Is proper following syntax?
> (slope %is% flat && elevation %is% is high) || area %is% large, form 
> %is% plateau
> Where I can find more information about syntax rules used in that 
> (fantastic!) package, except in "Generalised and Customisable Sets in 
> R" where is nothing about rules. Maybe rules comes from other, more 
> general rule syntax, if yes,I would be grateful for the source
> thanks and greetings
> Jarek
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I add this question because I cannot form any proper rule when I use ! 
(negation) or I use more complex rules rules with brackets I always receive:

Error in gset_charfun(x) : Argument 'x' must be a generalized set.

in fact function fuzzy_inferance works only if I use maximum two 
arguments rules without brackets.


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