Question 3(a)

(a)

Suppose you have a relation r(X,Y) that is true of there is a word in the word list below with first letter X and second letter Y.

The word list is:

add	arc	bad	bud
cup	dip	fad	odd

Suppose the domain of X is {a,b,c,d} and that of Y is {a,d,i,r}.

(i)

[3 marks] Is the arc <X,Y> arc consistent? If so, explain why. If not, show what element(s) can be removed from a domain to make it arc consistent.

(ii)

[3 marks] Is the arc <Y,X> arc consistent? If so, explain why. If not, show what element(s) can be removed from a domain to make it arc consistent.