# 📐  L2 Spec — Arterial Spin Labeling (ASL) MRI Mismatch-Only Spec

**ID:** `L2-057-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-057`](/artifact/l1/L1-057)

> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.5 · **Delta tier:** 5
> **⛓ On-chain block:** 41552980

---

## 1. Domain Ω

**Type:** `range`

| Parameter | Unit | Range |
|---|---|---|
| H | px | 32 |
| W | px | 32 |
| Z | — | 4 – 64 |
| Pld ms | ms | 500 – 3500 |
| Snr db | dB | 0.0 – 30.0 |
| Motion | — | 0.0 – 0.5 |
| Labeling efficiency | — | 0.5 – 1.0 |
| Noise amplification | — | 0.0 – 0.3 |
| N label control pairs | — | 5 – 200 |
| Arterial transit time | — | 500 – 3000 |

## 2. Tolerance (ε)

**Type:** `fn`

```
7.0 + 0.3 * SNR_dB + 5.0 * labeling_efficiency - 10.0 * motion - 0.002 * (arterial_transit_time - 1500)
```

## 3. Difficulty

| Property | Value |
|---|---|
| Difficulty score | 0.5 |
| Delta tier | 5 |

## 4. Fingerprint

`e7e3970937d06e5ea8a0c80ef3abdfc9b880af42f33696ebd8f6d8c667845fd9`

## 5. On-chain Registration

- **Chain hash:** `0xf820835f64ead6fbc5f9ec4020b161d746f2b107dc952dfa1b0e1f7e80b98dc9`
- **Chain tx hash:** `0x1fb1562997cf588ea945d28c502cb5cb284a704156185810fb1113dc2d68bc1d`
- **Chain block:** `41552980`

---

## File Mapping

This bundle consists of: `L2-057-001.md`, `L2-057-001.json`.

| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-057-001.md` | Source of truth — edit this | Human or LLM |
| `L2-057-001.json` | Structured metadata for the registry | LLM regenerates from the sections above |

**Prompt for your LLM after editing this Markdown:**

> Read the attached Markdown. Regenerate the sibling `.json` so every field matches.
> Preserve the schema documented in the rows above.
> Output each file in its own fenced code block tagged with the filename.
> Output only the JSON object.

_This Markdown was auto-synthesized from the catalog row for `L2-057-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._