In Boolean logic, with the rule ``IF X is A THEN Y is B'', the proposition X is A has to be observed to consider the proposition Y is B.
In fuzzy logic, a proposition ``X is '', close to the premise ``X is A'' can be observed to provide a conclusion ``Y is '' close to the conclusion ``Y is B '' [7].
A simple fuzzy inference can be represented as:
Rule | : IF | X is A THEN | Y is B | |
Fact | : | X is | ||
Conclusion | : | Y is |
To infer such a fuzzy inference we use a mechanism called generalized modus ponens. Here, we use one based on the fuzzy implication of Brouwer-Gödel [6] expressed by:
Remark: Assume the operator of the implication of Brouwer-Gödel and the combination operator, the formula (2) can be expressed by that we use now to simplify notations.