	In crisp logic, the premise "x is A" can only be true or false. However, in a fuzzy rule, the premise "x is A" and the consequent "y is B" can be true to a degree, instead of entirely true or entirely false. This is achieved by representing the linguistic variables "A" and "B" using fuzzy sets. In a fuzzy rule, modus ponens is extended to "generalised modus ponens:."