True or false.
When a variable occurs in a logic programming goal, the interpreter is being asked whether that goal holds for all values of the variable.
When a variable occurs in a logic programming axiom, the interpreter is being told that axiom holds for all values of the variable.
In logic programming, a variable in an axiom might be used as an input variable sometimes and as an output variable at other times, when computation uses that axiom.
Show the logic programming search tree for goal (member(X, [3,4,5]), member(X, [4])), up to the point where a success is found. The definition of the member predicate is as follows, written in Prolog syntax.
member(M, [M|X]).
member(M, [X|T]) :- member(M, T).
In a logic programming style, write axioms for computing predicate prefix(X, Y ), which is true just when list X is a prefix of list Y. For example, prefix([2,4,6], [2,4,6,8,10]) is true. Every list is a prefix of itself.
In a logic programming style, write axioms for computing predicate allsame(X ), which is true just when all members of list X are the same. For example, allsame([5,5,5]) is true, as is allsame([a,a]), but allsame([2,4,4]) is false. Note that allsame([]) is true, and allsame([b]) is true.
In a logic programming style, write axioms for computing predicate samelength(X, Y ), which is true just when X and Y are lists that have the same length.
The append predicate is defined as follows in Prolog.
append([], Y, Y). append([A|X], Y, [A|Z]) :- append(X, Y, Z).You would like to define a predicate double(X ), which is true if list X has the form Y ++ Y, for some Y. For example, double([a,b,c,a,b,c]) is true, but double([a,b,c,a]) is false.
Which of the following is a correct definition of double in Prolog?
Using the correct definition of predicate double from the preceding exercise, can a Prolog interpreter handle goal double(Z ), where Z is an unbound variable? If so, what will it do? If not, why not?
You would like to write a definition of predicate member, where member(X, L) is true if X is a member of list L. Which of the following is a correct definition of member?