Bartender

BARTENDER is a backward-chaining production system with rules given below. Given the facts and the set of hypotheses on the next page,(which should be tested in the given order), simulate BARTENDER's behavior.

Indicate your answer by showing the sequence in which the rules fire.

Specifically, at each step, give me the hypothesis under investigation, and then the rule that fires. BARTENDER stops as soon as one answer is obtained.

* Note that when more than one rule has a consequent matching the current problem, those rules are tried in the order given in the list.

Similarly, when a consequent matches, the antecedents are tested in the order given in the rule.

Rule B1 If expensive wine is indicated

it is New Year's Eve

then Bond's Champagne

Rule B2 If expensive wine is indicated

entree is steak

then Chateau Earl of Bartonville Red

Rule B3 If cheap wine is indicated

entree is chicken

guest is not well liked

then Honest Henry's Apple Wine

Rule B4 If cheap wine is indicated

entree is unknown

then Toe Lakes Rose

Rule B5 If beer is indicated

entree is Mexican

then Dos Equis

Rule B6 If beer is indicated

then Coors

Rule B7 If guest is a health nut

then Glop

Rule B8 If guest is a health nut

carrots are not to be served

then carrot juice

Rule B9 If wine is indicated

guest should be impressed

then expensive wine is indicated

Rule B10 If wine is indicated

then cheap wine is indicated

Rule B11 If guest is sophisticated

then wine is indicated

Rule B12 If entree is Mexican

then beer is indicated

Rule B13 If guest is not well liked

entree is catered by Death-wish Caterers

then beer is indicated

Rule B14 If true

then water

• Dos Equis
• Coors
• Glop
• Carrot juice
• Bond's Champagne
• Chateau Earl of Bartonville Red
• Toe Lakes Rose
• Honest Henry's Apple Wine
• Water

Now here are some facts to assume true, if inquiry is made:

• Entree is catered by Death-wish Caterers
• Guest is not well liked
• Guest is sophisticated
• It is New Year's Eve
• The entree is chicken

• Carrots are not to be served
• Entree is unknown
• Guest is a health nut
• Guest should be impressed
• The entree is steak
• Entree is Mexican

Now suppose BARTENDER is a forward-chaining production system.

Suppose the facts are known to the system in the order listed below and the hypotheses (consequent clauses) are known as soon as the rule is determined true (i.e., when the forward-chainer finds a match and allows a rule to fire.)

a) Show the chain of reasoning (i.e., the rules that are "observed") as

BARTENDERII reaches its first answer.

b) Show the chain of reasoning to reach its second answer.

• Entree is catered by Death-wish Caterers
• Carrots are not to be served
• Guest is not well liked
• Entree is unknown
• Guest is sophisticated
• Guest is a health nut
• It is New Year's Eve
• Guest should be impressed
• The entree is chicken