SPaDE

Knowledge Repository (KR)

This directory contains the implementation and specifications for the Knowledge Repository component of the SPaDE project.

Overview

The Knowledge Repository is a core component of the SPaDE architecture that provides a distributed, shared repository for declarative knowledge. It breaks with the traditional LCF paradigm by decoupling knowledge storage from the deductive kernel, enabling a more flexible and scalable architecture.

Key Features

• Universal Representation: Uses Cambridge HOL as a universal abstract representation for all declarative knowledge
• Distributed Architecture: Supports widely distributed shared knowledge repositories
• Version Control: Maintains versioned contexts for knowledge evolution
• Multi-language Support: Supports diverse concrete syntaxes through abstract HOL representation
• Consistency Management: Ensures logical consistency across distributed repositories

Architecture

The Knowledge Repository is structured around the concept of contexts - versioned signatures that contain:

• Type assignments for constant names
• Constraints (Boolean terms) on those names
• Metadata and relationships to other contexts

Core Concepts

• Context: A signature with type assignments and constraints
• Extension: Conservative additions to existing contexts
• Constraint: Boolean terms that must be satisfied
• Metadata: Contexts that describe other contexts

Directory Structure

kr/
├── README.md              # This file
├── src/                   # Source code implementation
├── specs/                 # Formal specifications
├── tests/                 # Test suite
└── docs/                  # KR-specific documentation

Documentation

• Knowledge Repository Overview - Main specification
• Universality Argument - Justification for HOL universality
• Formal Specifications - Mathematical specifications
• API Documentation - Interface documentation

Implementation Status

Current Status: Conceptual design phase

• High-level architecture defined
• Core concepts identified
• Formal specifications complete
• Implementation started
• Test suite created

Related Components

• Deductive Kernel (dk/): The logical inference engine that operates on KR contexts
• API Layer: Interfaces for accessing and manipulating knowledge
• Tools: Parsers, generators, and utilities for working with knowledge

Development Priorities

1. Complete formal specifications for context management
2. Implement core context operations (create, extend, query)
3. Design distributed consistency protocols
4. Create concrete syntax parsers
5. Build test suite and validation tools

Contributing

See the main project CONTRIBUTING.md for general guidelines.

For KR-specific development:

1. Review the formal specifications in specs/
2. Follow the architecture defined in docs/
3. Add tests for all new functionality
4. Update documentation for any API changes

References

• Cambridge HOL - The logical foundation
• LCF Paradigm - Traditional approach we’re evolving from
• Distributed Systems - Background on distributed architectures

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