# 📐  L2 Spec — Functional Near-Infrared Spectroscopy (fNIRS) Mismatch-Only Spec

**ID:** `L2-065-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-065`](/artifact/l1/L1-065)

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

---

## 1. Domain Ω

**Type:** `range`

| Parameter | Unit | Range |
|---|---|---|
| Snr db | dB | 0.0 – 35.0 |
| Motion | — | 0.0 – 0.5 |
| N sources | — | 4 – 128 |
| N detectors | — | 4 – 128 |
| Sampling hz | Hz | 1 – 100 |
| Ambient light | — | 0.0 – 0.3 |
| Optode coupling | — | 0.3 – 1.0 |
| Scalp blood flow contamination | — | 0.0 – 0.5 |

## 2. Tolerance (ε)

**Type:** `fn`

```
10.0 + 0.3 * SNR_dB + 6.0 * optode_coupling - 10.0 * scalp_blood_flow_contamination - 8.0 * motion
```

## 3. Difficulty

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

## 4. Fingerprint

`29e1745f39e83f893aba6f4cb158edebd2bee8d01c3add9f15f7e04d1332bdef`

## 5. On-chain Registration

- **Chain hash:** `0xa85a674fe405515a58256c4d5be56fdd8c0f29a824ba899f5d0f67517e014ea9`
- **Chain tx hash:** `0xddede3cbc2b6db4cdebd97f340721b53f1942513b80587ba99b9c57c79d9759e`
- **Chain block:** `41552980`

---

## File Mapping

This bundle consists of: `L2-065-001.md`, `L2-065-001.json`.

| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-065-001.md` | Source of truth — edit this | Human or LLM |
| `L2-065-001.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 `L2-065-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._