Fundamentals of Logic Programming - Vocabulary Flashcards

Forty-four vocabulary flashcards covering core concepts in Prolog and logic programming.

Axioms (Facts and Rules)

Facts and rules that form the knowledge base or theory of a logic program; axioms are assumed truths, rules are implications between facts.

Facts

Statements assumed true that represent basic knowledge.

Rules

Logical implications or relationships that define how new information can be inferred.

Goal Statements

Queries the programmer wants to prove or satisfy; the desired outcomes.

Axioms as a Theory

The collection of facts and rules that forms the knowledge base or theory of the logic program.

Goal Statements as Theorems

Theorems or propositions that the programmer aims to prove or derive from the axioms.

Computation as Deduction

Computation involves deducing new information from the axioms to prove the goal statements.

Interpreter

The component that finds a set of axioms and inference steps that lead to the proof of the goal statements.

Inference

The process of deducing conclusions by applying logical rules to facts.

Proof

The successful determination of a collection of axioms and inference steps that imply the goal statements.

Predicate

A relation (a tuple) that defines a logical connection between its arguments.

Relational Programming

Prolog programming paradigm where relations (predicates) express connections rather than functions.

N-ary Relations

Predicates that involve more than two entities; arity can be greater than 2.

parent/2

A simple relation/fact where parent(tom, bob) defines a parent-child relation; the /2 denotes arity two.

Directionality in Parameters

In Prolog, parameters are not strictly inputs or outputs; their roles can vary by context.

In parameters

Inputs in traditional languages; Prolog does not fix in/out—variables can be used as inputs.

Out parameters

Outputs; variables become bound to produce results when queried.

Knowledge Base

The initial set of facts and rules for a logic program.

Conjunction

Expressed with a comma; all goals separated by the comma must be satisfied.

Disjunction

Expressed with a semicolon; at least one of the goals must be true.

Implication

The ':-' symbol in Horn clauses reads as 'if' or 'is implied by'.

Negation

Negation (not) expresses that a goal should not be true; often used as not(P) in Prolog.

Variables

Unknown values or placeholders; usually start with a capital letter or underscore.

Don’t-Care Variable

The underscore '_' denotes a placeholder where the value is irrelevant.

Comments in Prolog

Actual code comments: single-line using % and multi-line using /* … */.

Atoms

Constants representing names or identifiers; start with a lowercase letter or be quoted.

Numbers

Integers and floating-point numbers, including scientific notation.

Arity

The number of arguments a predicate takes; e.g., loves/2 vs loves/3.

Predicate Name

The name of a predicate; typically starts with a lowercase letter.

Arguments

The terms inside a predicate; can be constants, variables, or complex terms.

Arity distinction

Predicates with different arities are distinct (e.g., loves/2 vs loves/3).

Horn Clauses

A rule form H:-B1,B2,…,Bn (or a fact if there is no body).

Head and Body

In a Horn clause, the head is the relation; the body contains the conditions.

Rule vs Fact

A fact has no body; a rule has a head and a body.

Principle of Resolution

A reasoning principle: resolve clauses to derive a goal from facts and rules.

Unification

Binding variables to make two terms identical; central to Prolog execution.

Backtracking

Exploring alternative paths when a particular search path fails.

Unification: Constant

A constant unifies only with itself.

Unification: Variable

A variable can unify with anything (constants, variables, or structures).

Unification extends recursively

Unification applies not just to top-level terms but to subterms inside compounds.

Equality operator =

In Prolog, equality is implemented via unification using the = operator.

Conjunctive query

A query with multiple goals joined by a comma; all must be true.

Disjunctive query

A query with multiple goals joined by a semicolon; at least one must be true.

Lists

A fundamental data structure for representing sequences of elements in Prolog.