fuzzy logic

Page numbers are for draft copy at present; they will be replaced with correct numbers when final book is formatted. Chapter numbers are correct and will not change now.

Fuzzy logics are one of the forms of fuzzy reasoning. They assign levels of 'truth' to varables rater than the dichotomous true/false of Boolean logic. This is used to capture the levels of uncertainty we have in real life about many things. So, for example, we might have:
    is_summer=1 -- definitely true
    feel_like_break=0.7 -- more true than not
    will_stay_fine=0.2 -- closer to false (UK weather!)
Logical operators AND and OR are converted into max and min , which correspond to the normal logic meanings for true/false values. We can then create a rule such as:
    go_for_a_picnic   =   is_summer AND ( feel_like_break OR will_stay_fine
        =   min ( 1, max( 0.7, 0.2 ) )   =   min(1,0.7) = 0.7

Used on Chap. 3: pages 45, 52

Also known as fuzzy