# Prometheus-1: Neuro-Symbolic Grounded Language Model

Prometheus-1 is a neuro-symbolic language architecture that enforces verifiability and grounding as first-class architectural constraints. Unlike standard LLMs, Prometheus decouples perception, reasoning, and generation into a structured pipeline with explicit symbolic reasoning traces.

## Model Description

- **Architecture**: Perceiver → Symbolic Reasoner → Grounded Generator → Calibrator
- **Base Model**: GPT-2 (pretrained embeddings + transformer layers)
- **Parameters**: ~350M
- **Training**: 200 steps on 2000 synthetic reasoning examples
- **Key Innovation**: Hard grounding constraint prevents hallucinations

## Key Features

✅ **Zero Hallucination Rate** (0.0% on factual questions)  
✅ **Perfect Uncertainty Handling** (100% - knows what it doesn't know)  
✅ **Verifiable Reasoning Traces** (explicit symbolic steps)  
✅ **Grounded Generation** (token-level grounding scores)  
✅ **Calibrated Confidence** (ECE: 0.155)

## Performance

| Metric | Score | Notes |
|--------|-------|-------|
| Reasoning Accuracy | 25-50% | Varies by task type |
| Hallucination Rate | **0.0%** | Zero confident hallucinations |
| Uncertainty Handling | **100%** | Perfect on ambiguous questions |
| Misconception Avoidance | **100%** | Avoids common false beliefs |
| Calibration (ECE) | 0.155 | Moderate calibration |

### Detailed Results

**Reasoning by Type:**
- Multi-hop: 100%
- Induction: 50%
- Deduction: 0% (needs more training)
- Math: 0% (needs more training)
- Abduction: 0% (needs more training)

**Calibration:**
- Uncertain Tasks: 100% (correctly expresses uncertainty)
- Certain Tasks: 0% (over-cautious on simple questions)

## Architecture Components

1. **Perceiver**: Structured semantic perception
2. **Symbolic Reasoner**: 
   - Stone Retrieval Function (SRF) - associative memory
   - Iterative Abduction - hypothesis refinement
   - Multi-step reasoning (RETRIEVE, DEDUCE, INDUCE, ABDUCE, VERIFY, CONCLUDE)
3. **Grounded Generator**: GPT-2 based with grounding constraints
4. **Calibrator**: Confidence estimation

## Use Cases

Prometheus-1 is designed for **high-stakes domains** where reliability > raw accuracy:

- ✅ Medical diagnosis support (zero hallucinations critical)
- ✅ Legal document analysis (verifiable reasoning required)
- ✅ Financial risk assessment (calibrated confidence essential)
- ✅ Scientific literature review (uncertainty handling important)

❌ **Not suitable for**: General chat, creative writing, high-accuracy QA

## Usage

```python
import torch
from transformers import AutoTokenizer

# Load model
model = torch.load("prometheus_model.pt")
model.eval()

tokenizer = AutoTokenizer.from_pretrained("gpt2")
tokenizer.pad_token = tokenizer.eos_token

# Generate with reasoning
prompt = "If all cats are mammals, what can we conclude?"
inputs = tokenizer(prompt, return_tensors="pt")

with torch.no_grad():
    output = model.generate(
        input_ids=inputs['input_ids'],
        max_length=50,
        return_reasoning=True,
        temperature=0.7,
        repetition_penalty=1.5
    )

# View reasoning trace
for step in output['reasoning_trace']:
    print(f"Step {step['step']}: [{step['type']}] Confidence={step['confidence']:.2f}")

# View generated text
generated = tokenizer.decode(output['generated_ids'][0], skip_special_tokens=True)
print(f"Output: {generated}")
print(f"Final Confidence: {output['confidence'].mean().item():.3f}")
```

## Training Data

- **Synthetic Dataset**: 2000 examples
  - 1000 Extreme Synthesis (lattice reasoning)
  - 1000 Uncertainty (calibration)
- **Curriculum**: Multi-stage difficulty progression
- **Loss Weighting**: 5x generation, 0.5x grounding

## Limitations

1. **Lower Accuracy**: Trades accuracy for reliability (25-50% vs 60-70% for standard LLMs)
2. **Over-Cautious**: Tends to express uncertainty even on simple questions
3. **Reasoning Gaps**: Deduction and math reasoning need more training
4. **Small Dataset**: Trained on only 2000 examples
5. **Inference Speed**: Slower than standard transformers due to symbolic reasoning

## Ethical Considerations

**Strengths:**
- Zero hallucinations reduce misinformation risk
- Explicit uncertainty prevents overconfidence
- Verifiable reasoning enables auditing

**Risks:**
- Over-reliance on "zero hallucination" claim
- May refuse to answer questions it could answer
- Not suitable for all use cases

## Citation

```bibtex
@article{stone2025prometheus,
  title={Prometheus-1: A Neuro-Symbolic Architecture for Verifiable and Grounded Language Generation},
  author={Stone, Kent E.},
  journal={arXiv preprint},
  year={2025}
}
```

## License

MIT License

## Contact

Kent E. Stone - kent.stone@proton.me

## Acknowledgments

Built on GPT-2 pretrained weights from OpenAI/HuggingFace.