---
title: "mova-nautilus-layer — Mova code model"
description: "Mova code model of tools/nautilus/src/layer.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/tools/nautilus/src/layer.rs.groupant/"
---
Elamur: [Mova](https://md.mova.elamur.ai/free/en/) · [Dictionary](https://md.dictionary.elamur.ai/free/en/) · [Research](https://md.research.elamur.ai/free/en/) · **Groupants**

This page as HTML: <https://groupants.elamur.ai/free/en/mova/tools/nautilus/src/layer.rs.groupant/>

# mova-nautilus-layer

The groupant beside tools/nautilus/src/layer.rs in the Mova repository: what the code computes, what it never does, how to go back from its outputs, its invariants, cost and checks.

## Facts

- **kind:** groupant
- **status:** partial source bound model
- **source:** [`tools/nautilus/src/layer.rs`](https://github.com/ElamurAI/mova-free/blob/main/tools/nautilus/src/layer.rs)
- **source SHA-256:** `6a4861575761ca3e…`
- **repository folder:** [`tools/nautilus/src/layer.rs.groupant`](https://github.com/ElamurAI/mova-free/tree/main/tools/nautilus/src/layer.rs.groupant)
- **repository commit:** `48f2e6f74146`

> **Implementation material.** A Mova code model describes this code at one source revision: partial models, finite checks and their stated scope. It is not a reviewed general exposition, and its labels are shown as written, never raised.

## Components

| component | label | where |
|---|---|---|
| **approximant** | partial | [Forward approximant](#forward-approximant) |
| **ast** | partial | `syntax.json` |
| **composition** | partial | [Composition](#composition) |
| **cost** | partial | [Cost](#cost) |
| **descriptant** | present | [Descriptant](#descriptant) |
| **invariant** | partial | [Invariant](#invariant) |
| **tests** | finite evidence | [tests](#tests) |

## Obernants

The typed relations around the forward model: the behaviour complement (what the code never does), the reverse reconstruction (every input compatible with an output) and specialised views.

| id | type | label | where |
|---|---|---|---|
| `behavior_complement` | behavior_complement | partial source derived model | [behavior_complement](#behavior-complement) |
| `reverse_reconstruction` | reverse_reconstruction | partial source derived model | [reverse_reconstruction](#reverse-reconstruction) |

## Model text


### model

## mova-nautilus-layer

### Descriptant

A dictionary layer from annotated units, natively: content lemmas (NOUN/VERB/ADJ/ADV) counted, top N by count, documents, lemma; part of speech and meaning from the pupils' dictionary; a counted sense (uses, documents, UPOS share, classes, co-occurring words); up to three examples with source ids; the school-layer TSV with a draft line; stats and parse_rows. Source: `tools/nautilus/src/layer.rs`.

### Forward approximant

units -> count (BTreeMap per lemma: uses, documents, UPOS, classes, co-occurrence, unit order) -> sort (count desc, documents desc, lemma) -> take top -> Row{word, base pos/meaning or UPOS name, counted sense, examples (new document first, 20..220 chars, source order), draft note} -> render (HEAD, draft line, rows).

### Invariant

Same units, base and source give the same bytes; rows <= top; every example ends with its unit id; parse_rows(render(rows)) == rows for tab-free rows.

### Cost

O(tokens log lemmas) counting plus O(L log L) sorting.

### Composition

Parent: `nautilus`. Parent: nautilus. Used by animal::make, work::DictJob and mova-turtle::make. State: Pure functions over in-memory units.

### behavior_complement

Does not write senses, disambiguate meanings, lemmatize itself, read proper nouns, function words or tokens with digits, or call any model; the meaning is copied, not checked against the source. Evidence status: source-derived model with finite checks, not a proof.

### reverse_reconstruction

From a layer one recovers the selected lemmas, their counts, documents, classes, top co-occurring words and chosen example ids; not the units that were not chosen, nor the annotation of each token. No unique inverse is claimed.

### Epoch 2026-11-04

First model, written with the source; no prospective prediction is claimed beyond the checks.

### tests

#### Checks

Command: cargo test --manifest-path tools/nautilus/Cargo.toml --offline --locked with MOVA_OCTOPUS_TEST_MODEL=$MOVA_DATA/download/0/0.4/en.bin (15 unit + 2 English tests; two identical runs on 2026-11-04).

Negative controls 2026-11-04 (each red, restored): no operator-word check; no terminal-id check; a limit not stopping the loop; stats drafting instead of reading.
These are finite fixtures; no teacher or model was called; not a proof.