# 📐 L2 Spec — Gravity Field Inversion — density imaging Mismatch-Only Spec
**ID:** `L2-279-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-279`](/artifact/l1/L1-279)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.48 · **Delta tier:** 5
> **⛓ On-chain block:** 41554067
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| H | px | 32 – 2048 |
| W | px | 32 – 2048 |
| Z | — | 8 – 512 |
| Snr db | dB | 0 – 40 |
| Tidal error | — | 0.0 – 0.2 |
| N observations | — | 64 – 100000 |
| Background error | — | 0.0 – 0.3 |
| Terrain correction error | — | 0.0 – 0.2 |
## 2. Tolerance (ε)
**Type:** `fn`
```
2.0 + 10.0*terrain_correction_error + 5.0*tidal_error + 5.0*background_error
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.48 |
| Delta tier | 5 |
## 4. Fingerprint
`dd98cf914be2cac6c17907dd16e80bb1d5f164236bd43a15179ee83636df815b`
## 5. On-chain Registration
- **Chain hash:** `0xdce2c9e024bf1ed367fee296f92dbaceb998fa237ae2627d2a26105fc4b2ebbf`
- **Chain tx hash:** `0xfe917774ff5ad831b4d01c30d093f925c5b261702ab3e14a448ee1f3ece3e93f`
- **Chain block:** `41554067`
---
## File Mapping
This bundle consists of: `L2-279-001.md`, `L2-279-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-279-001.md` | Source of truth — edit this | Human or LLM |
| `L2-279-001.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 `L2-279-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._