Review Questions

(Assignment by Mr Tri Djoko Wahyono)

1. What are three primary uses of symbolic logic in formal logic?

– to express propositions

– to express the relationships between propositions, and

– to describe how new propositions can be inferred from other propositions that are assumed to be true.

2. What are the two parts of a compound term?

– Two parts of a compound term are: a functor, which is the function symbol that names the relation, and an ordered list of parameters, which together represent an element of the relation.

3. What are the two modes in which a proposition can be stated?

– Propositions can be stated in two modes: one in which the proposition is defined to be true, and one in which the truth of the proposition is something that is to be determined. In other words, propositions can be stated to be facts or queries.

4. What is general form of a proposition in clausal form ?

-B1 U B2 U . . . U Bn C A1 n A2 n . . . n Am

5. What are antecedents? Consequents?

– Antecedents are the right side of clausal form propositions, whereas Consequents are the left side of clausal form propositions, because it is the consequence of the truth of the antecedent.

6. Give general definitions of resolution and unification

– Resolution : inference rule that allows inferred propositions to be computed from given propositions, thus providing a method with potential application to automatic theorem proving.

Unification : Process of determining useful values for variables.

7. What are the forms of Horn clauses?

– Horn clauses can be in only two forms: They have either a single atomic proposition on the left side or an empty left side. The left side of a clausal form proposition is sometimes called the head, and Horn clauses with left sides are called headed Horn clauses. Headed Horn clauses are used to state relationships, such as likes( bob, trout ) likes( bob, fish ) x fish( trout )

11. What is an uninstantiated variable?

– An uninstantiated variable is a variable that has not been assigned a value.

13. What is a conjunction?

– Conjunctions contain multiple terms that are separated by logical AND operations.

Problem Set

1.”All predicate calculus propositions can be algorithmically converted to clausal form”. Is this statement true or false?

– This statement is true. Nilsson (1971) gives proof that this can be done, as well as a simple conversion algorithm for doing it.

2. Describe how a logic programming language is different from a general programming language.

– Programming that uses a form of symbolic logic as a programming language, unlike other general programming language, is often called logic programming; languages based on symbolic logic are called logic programming languages, or declarative languages.

10. Using the internet for reference, find some of the applications of expert systems.

– Expert system in healthcare: The Electronic health record (EHR) is designed to replace the traditional medical and bring together a more versatile, expansive and robust expert system to provide greater quality care.

– Expert systems in the financial field: Loan departments are interested in expert systems for morgages because of the growing cost of labour, which makes the handling and acceptance of relatively small loans less profitable.

– A new application for expert systems is automated computer program generation. Funded by a US Air Force grant, an expert system-based application (hprcARCHITECT) that generates computer programs for mixed processor technology (FPGA/GPU/Multicore) systems without a need for technical specialists has recently been commercially introduced.