- Let a be a crisp number. We might define a truth value for the fuzzy statement "x <= a" as follows:
- value =
1
if x <= a (using the normal definition of <=)
- value = (1 + a - x) if a <= x <= a+1
- value =
0
if x > a+1
Draw the truth function for the fuzzy statement "x <= 10"
- Let a be a crisp number. We might define a truth value for the fuzzy statement "x >= a" as follows:
- value = 0
if x < a-1
- value = (1 + x - a) if a-1 <= x <= a
- value
= 1
if x >= a
Draw the truth function for the fuzzy statement "x >= 5"
- Using the definitions just given, sketch the truth functions for each of the following fuzzy statements
- "x is <= 5 and x is >= 6"
- "x is <= 5 or x is >= 6"
- "x is >= 2 and x is <= 4"
- "x is >= 2 or x is <= 4"
- "x is >= 4 and x is <= 4"
- How does part 5. of Exercise 3. relate to the concept of numeric equality in fuzzy logic?
- Let P(x) and Q(x) be fuzzy truth functions, each of which can only
give truth values of 0, 0.5, and 1. That is, for all x P(x) is in
the set {0, 0.5, 1} and Q(x) is in the set {0, 0.5, 1}
Recall the Kleene-Dienes definition of implication: "a -> b" is equivalent to "(not a) or b"
Compute the truth table for the fuzzy statement "(P(x) and (P(x) -> Q(x))) -> Q(x)"
How does this compare for the same truth table in crisp logic (where P(x) and Q(x) can only be "true" or "false")?