# Strategy 1: Multi-Strategy Implementation Archive

[← Back to Archive](../README.md) | [Documentation →](docs/) | [Exclusion Theory →](../../README.md)

## Directory Structure

```
strategy1_multi/
├── README.md               # This file - multi-strategy archive overview
├── semantic.py            # Multi-strategy semantic implementation
├── operators.py           # 12 exclusion operator strategies (15 operator classes)
├── examples.py            # Test examples (34 examples)
└── docs/                  # Strategy documentation
    ├── PLAN_1.md          # Original implementation plan
    ├── SEED_1.md          # Initial seed ideas
    └── old_strategies.md  # Documentation of all 12 strategies
```

## Overview

The **Multi-Strategy Implementation** represents the first major architectural approach to implementing hyperintensional exclusion semantics. This archived version demonstrates an ambitious attempt to solve the exclusion operator challenge through 12 different implementation strategies, ranging from quantified arrays to witness-driven approaches.

Within the exclusion theory development history, this implementation showcases early experimentation with various Z3 encoding techniques. While ultimately unsuccessful in fully resolving the false premise issue, it provided valuable insights about the complexity of encoding hyperintensional semantics and informed subsequent simplification efforts. The codebase grew to approximately 1000 lines in operators.py alone, demonstrating both the power and pitfalls of multi-strategy approaches.

This archive preserves 34 test examples that helped identify consistent issues across all 12 strategies, particularly the persistent false premise problem affecting 8-10 examples depending on the chosen strategy.

## Quick Start

```python
# Note: This is archived code - use for reference only
# To run historical tests:

# Default strategy (MS - Multi-Sort)
from strategy1_multi.operators import ExclusionOperator
from strategy1_multi.semantic import ExclusionSemantics

# Change strategy by modifying DEFAULT_STRATEGY
# Available: QA, QI, QI2, BQI, NF, NA, SK, CD, MS, UF, WD
# In operators.py: DEFAULT_STRATEGY = "MS"

# Run examples
# ./dev_cli.py -p -z src/model_checker/theory_lib/exclusion/archive/strategy1_multi/examples.py
```

## Subdirectories

### [docs/](docs/)

Historical documentation preserving the original implementation planning and strategy analysis. Contains PLAN_1.md outlining the initial multi-strategy vision, SEED_1.md with brainstorming notes on Z3 encoding approaches, and old_strategies.md providing detailed documentation of all 12 implementation strategies. Essential for understanding the evolution of exclusion semantics implementation.

## Documentation

### For Researchers

- **[Implementation Plan](docs/PLAN_1.md)** - Original multi-strategy vision and goals
- **[Strategy Documentation](docs/old_strategies.md)** - Detailed analysis of all 12 strategies
- **[Seed Ideas](docs/SEED_1.md)** - Initial brainstorming and approach considerations

### For Developers

- **[Semantic Implementation](semantic.py)** - Multi-strategy semantic framework
- **[Operator Implementations](operators.py)** - All 12 strategy implementations
- **[Test Examples](examples.py)** - 34 examples exposing strategy limitations

### For Historians

- **[Exclusion Theory History](../../history/)** - Complete development narrative
- **[Lessons Learned](../../history/LESSONS_LEARNED.md)** - Why this approach was simplified
- **[Strategy Evolution](../../history/STRATEGIES.md)** - Path to current implementation

## Implementation Strategies

The 12 strategies implemented in this archive:

### Array-Based Strategies
- **QA (Quantify Arrays)** - Direct array quantification
- **NA (Name Arrays)** - Named array approach

### Index-Based Strategies
- **QI (Quantify Indices)** - Basic index quantification
- **QI2 (Quantify Indices 2)** - Enhanced index quantification
- **BQI (Bounded Quantify Indices)** - Bounded quantification variant

### Function-Based Strategies
- **NF (Name Functions)** - Named function approach
- **UF (Uninterpreted Functions)** - Z3 uninterpreted functions

### Logic-Based Strategies
- **SK (Skolemized)** - Skolemization approach
- **CD (Constraint-Based)** - Pure constraint encoding
- **MS (Multi-Sort)** - Multi-sorted logic (default)
- **WD (Witness-Driven)** - Witness predicate approach

### Hybrid Strategies
- **HP (Hybrid Predicate)** - Combined approaches

## Examples

### Test Coverage

The archive includes **34 test examples** designed to stress-test the exclusion operator:

- Basic exclusion tests
- Complex nesting patterns
- Edge cases exposing false premise issues
- Strategy-specific validation examples

### Known Issues

**False Premise Problem**: 8-10 examples consistently produced false premises across all strategies, indicating a fundamental issue with the encoding approach rather than strategy-specific problems.

**Example Categories**:
- Working examples: ~24 (depending on strategy)
- False premise examples: 8-10
- Strategy-dependent behavior: 2-4

## Testing and Validation

### Running Historical Tests

```bash
# From ModelChecker root directory
cd /home/benjamin/Documents/Philosophy/Projects/ModelChecker/Code

# Run with default strategy (MS)
./dev_cli.py -p -z src/model_checker/theory_lib/exclusion/archive/strategy1_multi/examples.py

# To test different strategies, modify DEFAULT_STRATEGY in operators.py
```

### Strategy Comparison

Each strategy produced slightly different results:
- Most strategies: 8-10 false premises
- Best performers: MS, CD strategies
- Most problematic: QA, NA strategies

## Historical Significance

### Lessons Learned

1. **Complexity vs. Correctness**: Multiple strategies increased complexity without solving core issues
2. **Z3 Encoding Challenges**: Different encodings revealed consistent semantic problems
3. **Simplification Need**: Led to recognition that a simpler approach was needed

### Path Forward

This implementation directly influenced:
- Strategy 2 (Witness Predicate approach)
- Recognition of false premise as fundamental issue
- Decision to pursue cleaner, simpler semantics

### Preservation Value

This archive serves as:
- Reference for attempted solutions
- Documentation of design decisions
- Foundation for understanding current implementation

## References

### Related Documentation

- **[Strategy 2 Archive](../strategy2_witness/)** - Next iteration attempt
- **[Current Implementation](../../)** - Final simplified approach
- **[Implementation Story](../../history/IMPLEMENTATION_STORY.md)** - Complete narrative

### Technical Context

- Pre-2024 implementation
- Z3 version compatibility considerations
- Python ModelChecker framework integration

---

[← Back to Archive](../README.md) | [Documentation →](docs/) | [Exclusion Theory →](../../README.md)