Search results
Results From The WOW.Com Content Network
Under a declarative reading, the order of rules, and of goals within rules, is irrelevant since logical disjunction and conjunction are commutative. Procedurally, however, it is often important to take into account Prolog's execution strategy, either for efficiency reasons, or due to the semantics of impure built-in predicates for which the ...
A rule is called ground if all of its atoms (head and body) are ground. A ground rule R 1 is a ground instance of another rule R 2 if R 1 is the result of a substitution of constants for all the variables in R 2. The Herbrand base of a Datalog program is the set of all ground atoms that can be made with the constants appearing in the program.
In all of these languages, rules are written in the form of clauses: A :- B 1, ..., B n. and are read as declarative sentences in logical form: A if B 1 and ... and B n. A is called the head of the rule, B 1, ..., B n is called the body, and the B i are called literals or conditions. When n = 0, the rule is called a fact and is written in the ...
λProlog, also written lambda Prolog, is a logic programming language featuring polymorphic typing, modular programming, and higher-order programming.These extensions to Prolog are derived from the higher-order hereditary Harrop formulas used to justify the foundations of λProlog.
Prolog is a logic programming language that has its origins in artificial intelligence, automated theorem proving and computational linguistics. [1] [2] [3]Prolog has its roots in first-order logic, a formal logic, and unlike many other programming languages, Prolog is intended primarily as a declarative programming language: the program is a set of facts and rules, which define relations.
In pure Prolog, normal DCG rules with no extra arguments on the functors, such as the previous example, can only express context-free grammars; there is only one argument on the left side of the production. However, context-sensitive grammars can also be expressed with DCGs, by providing extra arguments, such as in the following example:
ProbLog is a probabilistic logic programming language that extends Prolog with probabilities. [1] [2] [3] It minimally extends Prolog by adding the notion of a probabilistic fact, which combines the idea of logical atoms and random variables. Similarly to Prolog, ProbLog can query an atom.
The choice rule in Line 1 "generates" all subsets of the set of edges. The three constraints "weed out" the subsets that are not Hamiltonian cycles. The last of them uses the auxiliary predicate r ( x ) {\displaystyle r(x)} (" x {\displaystyle x} is reachable from 0") to prohibit the vertices that do not satisfy this condition.