# 📐  L2 Spec — CACTI Mismatch-Only Spec (standard SCI video benchmark family)

**ID:** `L2-004` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-004`](/artifact/l1/L1-004)

> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** None · **Delta tier:** 5
> **⛓ On-chain block:** 41421561

---

## 1. Domain Ω

**Type:** `range`

| Parameter | Unit | Range |
|---|---|---|
| B | — | 4 – 32 |
| H | px | 32 – 1024 |
| W | px | 32 – 1024 |
| Dt | — | 0.0 – 0.1 |
| Dx | — | 0.0 – 1.0 |
| Dy | — | 0.0 – 1.0 |
| Eta | — | 0.9 – 1.0 |
| Gamma | — | 0.95 – 1.05 |
| Theta | — | 0.0 – 0.15 |
| Offset | — | 0.0 – 0.01 |
| Sigma n | N | 0.5 – 2.0 |
| Noise level | — | 0.001 – 0.1 |

## 2. Tolerance (ε)

**Type:** `fn`

```
26.0 + 1.5 * log2(B / 8) + 1.0 * log10(photon_count / 100)
```

## 3. Difficulty

| Property | Value |
|---|---|
| Delta tier | 5 |

## 4. Fingerprint

`f28e75d074bcad93eda64b48e9428602a6fed845442d3ef2a14f911ca9d701f6`

## 5. On-chain Registration

- **Chain hash:** `0x3d15686eff5758f77fac1ae4843e25499a87d0f5fcd2661023eb1b69228aa8f9`
- **Chain tx hash:** `0x731b8d06ff6ec0ccb82acade1e245a553fdabad98e40c7eeb72b01ed52548cfc`
- **Chain block:** `41421561`

---

## File Mapping

This bundle consists of: `L2-004.md`, `L2-004.json`.

| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-004.md` | Source of truth — edit this | Human or LLM |
| `L2-004.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 `L2-004`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._