Question 1: Use an example to explain the relationship between knowledge and symbol structures? What is meant by a knowledge representation language? List and briefly

Question 1:

1. Use an example to explain the relationship between knowledge and symbol structures?
2. What is meant by a knowledge representation language?
3. List and briefly explain the general requirements of a knowledge representation language.

Question 2: Explain the difference between forwarding chaining and backward chaining rule-based systems.

Question 3: Suppose that the rule base of a rule-based system contains the following rules:

[R1] If Fred is hairy then Fred is a mammal

[R2] If Fred has forward-pointing eyes then Fred is a predator.

[R3] If Fred is a mammal and Fred is a predator then Fred is a Cheetah.

While its working memory initially contains the following facts

[Fl] Fred is hairy.

[F2] Fred has forward-pointing eyes.

Show the steps by which a forward chaining system would infer that Fred is a Cheetah. Your answer should show which facts are added to working memory, in what order, and which facts and rules were used to add those facts.

Question 4: Family relations can be represented with first-order logic. Some family relationships can be found below:

R1: ∀x,y Father(x,y) <=>Parent(x,y) ∧ Male(x)

R2: ∀x,y Mother(x,y) <=>Parent(x,y) ∧ Female(x)

R3: ∀x,y Child(x,y) <=> Parent(y,x)

R4: ∀x,y Son(x,y) <=> Child(x,y) ∧ Male(x)

R5: ∀x,y Daughterky) <=> Child(x,y) ∧ Female(x)

R6: ∀x,y Sibling(x,y) <=>∃z Parent(z,x) ∧ Parent(z,y)

R7: ∀x,y Sibling(x,y) <=> Sibling(y,x)

R8: ∀x,y Uncle(x,y) <=> ∃z Parent(z,y) ∧ Sibling(x,z) ∧ Male(x)

R9: ∀x,y Aunt(x,y) <=> ∃z Parent(z,y) ∧ Sibling(x,z) ∧ Female(x)

R10: x,y Cousin(x,y) <=> ∃

R11: x,y Brother_in_Law(x,y) <= ∃ ∃

R12: x,y Sister_in_Law(x,y) <=> ∧ ∧ ∧ ∧ Male(x)

R13: ∀

Imagine that you live in a society with some strange rules:

• Nobody can get married to the cousin of his/her brother_in_law
• If somebody is single and his cousin has a daughter he has to get married to her
• If a girl is single and the brother in law of her aunt has a son, she has to marry him.

Answer these questions:

1. Use the family relation to represent the ‘strange’ rules of that society.
2. Now, we have the following people that live in that society:

“Martha is Mary’s mother, her father is Peter. Martha has only a sister, Lucy. Lucy is married to Alex and they have a son, Albert. Martha and Peter are married and have a son, John. Albert is married and has a daughter Ann. Mary, John, and Ann are singles. John has been told that he has to marry Ann.

Can this be true? Use backward chaining.