Knowledge Representation Questions and Answers

Answer: A

Temporal logic adds times or intervals to the ontology, so that a fact may hold at one moment and not at another and reasoning about change becomes possible. Computation duration, proof ordering and belief revision are different matters. Adding one further kind of entity to what a formalism assumes exists, and the machinery to quantify over it, is how each extension in this family is constructed.

Answer: B

Employment, ownership, location and almost every practically interesting relation hold during some interval and not others, and a representation without times can only describe a snapshot. Speed, standards and storage are not the reason. That the great majority of real facts are temporally qualified, while the simplest formalisms cannot say so, is why so much of knowledge representation is concerned with time in one form or another.

Answer: A

The number of arguments is the term's Arity.

In Prolog a complex term (compound term) consists of a functor and a list of arguments, such as likes(mary, wine). The number of arguments is its arity; this term has arity 2, and predicates are written with it, as likes/2.

An atom is a constant name such as mary. Numbers and constants are kinds of simple terms, not the count of arguments of a complex term.

Answer: C

The key places 'If ... then ...' in Predicate logic.

In predicate logic, 'if P then Q' is the implication \(P \rightarrow Q\), and knowledge is commonly written as implications over predicates, for example \(\forall x\, (\text{man}(x) \rightarrow \text{mortal}(x))\). Inference rules such as modus ponens then use these if-then statements to derive new facts.

Conceptual dependency represents the meaning of sentences with a small set of primitive acts, and scripts represent stereotyped sequences of events (such as visiting a restaurant). Neither is defined by if-then statements, and 'Formal' is not a representation scheme.