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Questions tagged [prolog]

Prolog is the most commonly used logic programming language. It supports non-deterministic programming through backtracking and pattern matching through unification.

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How to implement a Prolog interpreter in a purely functional language?

Is there a clear reference, with pseudo-code, on how to go about implementing a Prolog interpreter in a purely functional language? That which I have found so far seems to deal only with imperative languages, is merely a demonstration of Prolog…
Jimster
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What makes PROLOG Turing-complete?

I know that it can be proven PROLOG is Turing-complete by constructing a program that simulates a Turing machine like this: turing(Tape0, Tape) :- perform(q0, [], Ls, Tape0, Rs), reverse(Ls, Ls1), append(Ls1, Rs, Tape). perform(qf, Ls,…
Lenar Hoyt
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Paradox? Pure Prolog is Turing-complete and yet incapable of expressing list intersection?

Pure Prolog (Prolog limited to Horn clauses only) is Turing-complete. In fact, a single Horn clause is enough for Turing-completeness. However, pure Prolog is incapable of expressing list intersection. (Disequality, dif/2, would allow it to do it,…
MWB
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Can constraint satisfaction problems be solved with Prolog?

Is "party attendance" type of problems solvable in Prolog? For example: Burdock Muldoon and Carlotta Pinkstone both said they would come if Albus Dumbledore came. Albus Dumbledore and Daisy Dodderidge both said they would come if Carlotta Pinkstone…
Tegiri Nenashi
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How often is Prolog/ASP used in non-research areas?

I've just recently found out about KRR (Knowledge representation and Reasoning) and ASP, not hearing a thing about them before (except a bit about prolog). I've read a bit about them and one of their primary usage seems to be AIs. My question would…
FloriOn
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Proper terminology in Prolog/logical programming theory?

I have a good understanding of how to program using logic languages, but I'm currently writing up a paper describing some of my work, and I wanted to ensure that I wasn't abusing the proper terminology when describing logic languages. I have a few…
Joey Eremondi
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Efficient algorithm for factorizing symbolic sum of products

Given a sum of flat symbolic products like $axc + byc + ayc + bxc$, how can I efficiently factorize it as a product of sums like $(a+x)(b+y)c$? For my problem, the products are not commutative -- it's more like a sum-of-tuples becoming a…
Bruno Kim
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How does negation as failure work with variables?

Let's say we have the following rule: p -: X ≠ Y, X = Y Stating that $\forall x.y. x \neq y \land x = y \implies p$. Now let us suppose that we are searching for a proof of $p$. Such a proof does not exist, of course, but we will search for it. Our…
Christopher King
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How do we translate first order logic's universal quantifier (the $\forall$) and the existential quantifier (the $\exists$) to Prolog?

I'm trying to convert some English statements to first order logic statements and I'm trying to use Prolog to verify the translations. My question is: how do I convert a first order logic statement (having $\forall$ and $\exists$ quantifiers) into…
842Mono
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Programmatically checking equivalence of statements

So as part of a theorem-prover/checker, I'm using Prolog to try to determine the equivalence of statements that have been parsed into tree form, e.g. $x=2$ is represented as eq(x,2), or $x=2 \land y\leq z$ if and(eq(x,2),leq(y,z)), and I want to…
Harr
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Generalization of Horn clauses in logic programming?

As far as I understand, Prolog and related languages are restricted to inference rules of the form $$ p_1 \land \dots \land p_n \rightarrow q$$ which is equivalent to the Horn clause $$ \neg p_1 \lor \dots \lor \neg p_n \lor q$$ I'm wondering if…
Roland
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Open Standard Prolog Knowledge Bases

Are there any standard Prolog knowledge bases available anywhere that have the same purpose as Cyc, namely to encode generally accepted common sense and human knowledge? Typically containing generally accepted facts such as the ones given…
Nordlöw
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Horn clause to Prolog

At the needs of my HW at uni I need to transform some Horn clauses to Prolog but I cannot figure out how to do it. I found out some guides but they describe how to do it with only one fact. So can you give me a brief example on how to do it? Eg John…
Mario
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Convert FOL clauses to PROLOG

I am very new to PROLOG so it might be a very trivial question, but I absolutely have no idea how to solve it. There are 4 sentences I need to formulate into PROLOG code: All hounds howl at night. Anyone who has any cats will not have any…
Nagham
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What is the computation model of Prolog?

Several computation models have representative programming language counterparts, as, according to this answer, Snobol for rewriting systems, APL for combinators, Lisp/Scheme for lambda calculus, and off course the family of imperative languages for…
user_163417
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