Re: Problem with fuzzy rule implication

WSiler (
Sun, 9 Nov 1997 05:12:21 +0100 (MET)

> I believe that you can formulate any FL system without using a single "not"
>or "else" clause.

Certainly one can do this, by writing two rules. Example:

IF x > roughly 30 THEN age = "old" ELSE age = "young";

is equivalent to

IF x > roughly 30 THEN age = "old";

IF x <= roughly 30 THEN age = "young";

However, I see no gain in clarity in the second formulation; actually, the
first formulation seems clearer.

In fact, it is in my experience more likely that three or more fuzzy
alternatives will be used. For a single numeric variable, it is far more
likely that a fuzzy set of at least three descriptive words will be used
rather than only atwo alternatives such as "old" and "young" above, with
fuzzification using membership functions to get the confidences in the various

Bill Siler