prolog-core

Explain Prolog core concepts including facts, rules, queries, and backtracking.

1|Updated Mar 15, 2026

Search Tags:#queries #declarative #backtracking #unification #prolog #logic-programming #horn-clauses

Ready to run

npx skills add https://github.com/hafley66/claude-research --skill prolog-core

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: prolog-core
Source: https://github.com/hafley66/claude-research/tree/main/skills/prolog-core
Command: npx skills add https://github.com/hafley66/claude-research --skill prolog-core

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Prolog core concepts explained to help developers understand logic programming, unification, and backtracking without getting lost in syntax.

Core Features & Use Cases

Understand Horn clauses, facts, and rules, and how queries drive a proof search.
Learn declarative vs procedural reading and the closed-world assumption to reason about knowledge bases.
Apply these concepts to build small logic programs and explore related prolog-* skills.

Quick Start

Create a tiny Prolog program with parent facts and a grandparent rule to see unification and backtracking in action.

Frequently Asked Questions about prolog-core

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

What is Prolog logic programming and how does it differ from procedural languages?▼

Prolog logic programming defines relationships through declarative Horn clauses rather than procedural steps, allowing developers to state facts and rules while the engine handles execution via backtracking and unification.

How do I write a basic Prolog program with facts and rules?▼

To write a Prolog program, define facts such as parent relationships and rules like grandparent derivation, then run queries to trigger unification and backtracking against the knowledge base.

How does backtracking work in Prolog when a query fails?▼

Backtracking in Prolog re-evaluates previous goals by seeking alternative unification paths when a query fails, systematically exploring the knowledge base until it finds valid proof or exhausts all options.

What is the closed-world assumption in Prolog and when does it apply?▼

The closed-world assumption in Prolog treats any statement not provable from the knowledge base as false, applying to reasoning scenarios where developers need strict logical boundaries for logical inference.

Does Prolog use declarative or procedural reading for rules?▼

Prolog supports both declarative and procedural reading; declarative reading defines the logical relationships, while procedural reading explains how the engine executes rules through backtracking and unification.

Why does Prolog use Horn clauses for knowledge representation?▼

Prolog uses Horn clauses because they provide a computationally efficient subset of first-order logic, allowing facts and rules to be represented clearly while enabling automated theorem proving through queries.