---
title: "prag-feats-dictionary — Mova code model"
description: "Mova code model of prag/src/feats.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/prag/src/feats.rs.groupant/dictionary.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/prag/src/feats.rs.groupant/dictionary.groupant/>

# prag-feats-dictionary

The groupant beside prag/src/feats.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_fragment
- **status:** partial source bound model
- **source:** [`prag/src/feats.rs`](https://github.com/ElamurAI/mova-free/blob/main/prag/src/feats.rs)
- **source SHA-256:** `2a1a0bd6e43dd16f…`
- **covers:** Training-order per-slot dictionaries with complete previous-act vocabulary and explicit unseen sentinel. (bytes 16702–18871)
- **part of:** [prag-feats](https://md.groupants.elamur.ai/free/en/mova/prag/src/feats.rs.groupant/)
- **repository folder:** [`prag/src/feats.rs.groupant/dictionary.groupant`](https://github.com/ElamurAI/mova-free/tree/main/prag/src/feats.rs.groupant/dictionary.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 source model | [forward](#forward) |
| **ast** | partial | `../syntax.json` |
| **composition** | partial source model | [composition](#composition) |
| **cost** | partial source model | [cost](#cost) |
| **descriptant** | partial source model | [epoch-memory](#epoch-memory) |
| **invariant** | partial source model | [invariant](#invariant) |
| **tests** | partial source model | [checks](#checks) |

## 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 |
|---|---|---|---|
| `prag-feats-dictionary-behavior-complement` | behavior_complement | partial source model | [behavior-complement](#behavior-complement) |
| `prag-feats-dictionary-reverse-reconstruction` | reverse_reconstruction | partial source model | [reverse-reconstruction](#reverse-reconstruction) |
| `prag-feats-dictionary-coupling` | constraint_relation | partial source model | [coupling](#coupling) |
| `prag-feats-dictionary-observation-fiber` | information_loss | partial source model | [observation-fiber](#observation-fiber) |

## Model text


Training-order per-slot dictionaries with complete previous-act vocabulary and explicit unseen sentinel.

Source snapshot: 2a1a0bd6e43dd16f7284e993f30d0f4971c447c9e2080616033d19ac8693611f. All relations concern this snapshot on the stated admissible domain. Models are source-derived partial relations; finite fixtures are evidence, not general proofs. Complement is a conservative inner constraint model. Reverse reconstruction preserves all compatible antecedents conceptually; no enumerating solver is implemented.

### forward

build seeds prev with Act::ALL names then start, inserts each row value once in traversal order. id looks up slot map or UNSEEN; encode projects every supplied coordinate. Serialization skips index; reindex recreates per-slot maps from values. show uses '?' for UNSEEN and SLOTS names.

### behavior-complement

Universe: valid-width rows and built/reindexed dictionary plus candidate IDs. Excludes ID reuse for distinct values within a slot, unseen training values after build, missing Act IDs in prev, and encoding an absent value as an ordinary ID. No guarantee for deliberately malformed serialized duplicate values.

### reverse-reconstruction

Given values retain every training row history with identical per-slot first-appearance order and arbitrary repeats. Given UNSEEN retain every absent string, not one unknown spelling. Numeric IDs require dictionary and slot to interpret; they alone do not reconstruct rows.

### invariant

Slot index must be in dictionary range; non-UNSEEN show ID must be in values range. Rows longer than SLOTS panic; shorter rows encode shorter vectors. Reindex is required after deserialize; no automatic repair.

### cost

Expected total input string hashing/copy time and distinct-value storage. reindex copies every retained value; encode expected O(row string bytes); show allocates explanation string. No measured speedup or executable approximation error bound is claimed.

### coupling

Dict receives training rows after prev injection; it pre-seeds all acts so predicted but unseen training acts still encode. Persisted model users must reindex before id/encode. Model and eval callers maintain that lifecycle.

### observation-fiber

Training counts and repeated-row order are forgotten except first appearances. Serialized values retain decoding data but discard the hash index. UNSEEN collapses all unobserved values and show prints one '?'.

### composition

Dict receives training rows after prev injection; it pre-seeds all acts so predicted but unseen training acts still encode. Persisted model users must reindex before id/encode. Model and eval callers maintain that lifecycle. No child fragments; this is one scoped relation.

### checks

empty_row_literal_and_dictionary_roundtrip covers every empty feature coordinate, Act coverage, missing value, show, serde omission, reindex, equal encoding and serialized bytes. See the file-level evidence.md for exact log hashes and repeated run outcomes.

### epoch-memory

2026-10-30 wave13: initial source-bound model. Prospective model preceded edits. Existing normalization and quote rules were retained; tests expose their information loss. Source identity witness justified qualifying predecessor keys by Src. Annotation is isolated behind a private closure used by the production row wrapper; fixtures do not call or certify tokenizer/parser. AST is a partial syntax projection, macro bodies opaque; semantic AST, live model/corpus and general proof remain absent.