---
title: "roundtrip-world-codec — Mova code model"
description: "Mova code model of tools/roundtrip/src/world.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/tools/roundtrip/src/world.rs.groupant/codec.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**

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# roundtrip-world-codec

The groupant beside tools/roundtrip/src/world.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:** [`tools/roundtrip/src/world.rs`](https://github.com/ElamurAI/mova-free/blob/main/tools/roundtrip/src/world.rs)
- **source SHA-256:** `46d4429a5127b1a4…`
- **covers:** World residual codec (bytes 11506–21694)
- **part of:** [roundtrip-world](https://md.groupants.elamur.ai/free/en/mova/tools/roundtrip/src/world.rs.groupant/)
- **repository folder:** [`tools/roundtrip/src/world.rs.groupant/codec.groupant`](https://github.com/ElamurAI/mova-free/tree/main/tools/roundtrip/src/world.rs.groupant/codec.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 | [approximant](#approximant) |
| **ast** | partial | `../syntax.json` |
| **cost** | partial | [invariant-and-cost](#invariant-and-cost) |
| **descriptant** | present | [descriptant](#descriptant) |
| **invariant** | partial | [invariant-and-cost](#invariant-and-cost) |
| **tests** | bounded checks | [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) |
| `global_local_links` | global_local_links | partial source derived model | [global_local_links](#global-local-links) |
| `dedup_projection` | dedup_projection | partial source derived model | [dedup_projection](#dedup-projection) |
| `sentence_xor` | sentence_xor | partial source derived model | [sentence_xor](#sentence-xor) |
| `scope_precondition` | scope_precondition | partial source derived model | [scope_precondition](#scope-precondition) |

## Model text


### descriptant

#### World residual codec

2026-10-31 epoch: source scope bytes [11506,21694); Dedup/global-index map precedes decoder comparison; full patches compensate lost fields and XOR starts plus empty indices recover original sentence partition.

No annotator/model loading, live corpus, full suite, teacher, GPU or persistent-learning evidence. No executable percentage surrogate: categorical codecs/effects need a useful metric before future caps 1/2/5/10%.

### approximant

#### World residual codec

Dedup/global-index map precedes decoder comparison; full patches compensate lost fields and XOR starts plus empty indices recover original sentence partition.

Domain: bounded synthetic values, valid source-specific coordinates, nonoverflowing counts, available allocation; fixed environment controls. Relations are source-derived partial models with finite checks, not universal proofs.

### catalog

### behavior_complement

Subject: roundtrip-world-codec, source hash 46d4429a5127b1a462d90e5d350a0f440d440a6781edeab42a01d3bf124a3675, transition observation.

For World residual codec, excluded transitions violate the stated scoped rule: Dedup/global-index map precedes decoder comparison; full patches compensate lost fields and XOR starts plus empty indices recover original sentence partition. This is an inner source-derived exclusion under the domain, not a complement of arbitrary unseen runtime behavior.

Domain: bounded synthetic values, valid source-specific coordinates, nonoverflowing counts, available allocation; fixed environment controls. Relations are source-derived partial models with finite checks, not universal proofs.

Evidence: external wave32 rt_core receipt includes native-commands.json, exact named outcomes twice debug/twice release, raw status/log files, compiled production controls with byte restoration and paired syntax. Only named synthetic helpers execute; model_path/export and live CLI paths have representation/source evidence.

Status: partial source-derived model.

### reverse_reconstruction

Subject: roundtrip-world-codec, source hash 46d4429a5127b1a462d90e5d350a0f440d440a6781edeab42a01d3bf124a3675, transition observation.

Fix outputs and post-state of codec; compatible antecedents are all scoped inputs/pre-state satisfying: Dedup/global-index map precedes decoder comparison; full patches compensate lost fields and XOR starts plus empty indices recover original sentence partition. Fields outside this byte scope are held fixed; discarded fields remain ambiguous.

Domain: bounded synthetic values, valid source-specific coordinates, nonoverflowing counts, available allocation; fixed environment controls. Relations are source-derived partial models with finite checks, not universal proofs.

Evidence: external wave32 rt_core receipt includes native-commands.json, exact named outcomes twice debug/twice release, raw status/log files, compiled production controls with byte restoration and paired syntax. Only named synthetic helpers execute; model_path/export and live CLI paths have representation/source evidence.

Status: partial source-derived model.

### global_local_links

Subject: roundtrip-world-codec, source hash 46d4429a5127b1a462d90e5d350a0f440d440a6781edeab42a01d3bf124a3675, transition observation.

globalize adds sentence offset to quote/cause/next/link; localize uses wrapping_sub. Valid sentence-local indices and nonoverflowing totals are required for intended coordinate interpretation.

Domain: bounded synthetic values, valid source-specific coordinates, nonoverflowing counts, available allocation; fixed environment controls. Relations are source-derived partial models with finite checks, not universal proofs.

Evidence: external wave32 rt_core receipt includes native-commands.json, exact named outcomes twice debug/twice release, raw status/log files, compiled production controls with byte restoration and paired syntax. Only named synthetic helpers execute; model_path/export and live CLI paths have representation/source evidence.

Status: partial source-derived model.

### dedup_projection

Subject: roundtrip-world-codec, source hash 46d4429a5127b1a462d90e5d350a0f440d440a6781edeab42a01d3bf124a3675, transition observation.

fact_key includes kind/verb/neg/role ids/frame attrs/oblique ids but omits TAM, pronouns, links and mention modifiers. Distinct facts may collide; inserts preserve original frames regardless.

Domain: bounded synthetic values, valid source-specific coordinates, nonoverflowing counts, available allocation; fixed environment controls. Relations are source-derived partial models with finite checks, not universal proofs.

Evidence: external wave32 rt_core receipt includes native-commands.json, exact named outcomes twice debug/twice release, raw status/log files, compiled production controls with byte restoration and paired syntax. Only named synthetic helpers execute; model_path/export and live CLI paths have representation/source evidence.

Status: partial source-derived model.

### sentence_xor

Subject: roundtrip-world-codec, source hash 46d4429a5127b1a462d90e5d350a0f440d440a6781edeab42a01d3bf124a3675, transition observation.

decode starts is heuristic link grouping; R4 toggles symmetric difference with original starts, inserts recover removed frames, empties restore zero-frame sentences. nsents is external required input.

Domain: bounded synthetic values, valid source-specific coordinates, nonoverflowing counts, available allocation; fixed environment controls. Relations are source-derived partial models with finite checks, not universal proofs.

Evidence: external wave32 rt_core receipt includes native-commands.json, exact named outcomes twice debug/twice release, raw status/log files, compiled production controls with byte restoration and paired syntax. Only named synthetic helpers execute; model_path/export and live CLI paths have representation/source evidence.

Status: partial source-derived model.

### scope_precondition

Subject: roundtrip-world-codec, source hash 46d4429a5127b1a462d90e5d350a0f440d440a6781edeab42a01d3bf124a3675, transition observation.

World residual codec requires the coordinate/state assumptions of this fragment; inspect its exact byte range. Dedup/global-index map precedes decoder comparison; full patches compensate lost fields and XOR starts plus empty indices recover original sentence partition. Invalid arbitrary state is outside the reconstruction law.

Domain: bounded synthetic values, valid source-specific coordinates, nonoverflowing counts, available allocation; fixed environment controls. Relations are source-derived partial models with finite checks, not universal proofs.

Evidence: external wave32 rt_core receipt includes native-commands.json, exact named outcomes twice debug/twice release, raw status/log files, compiled production controls with byte restoration and paired syntax. Only named synthetic helpers execute; model_path/export and live CLI paths have representation/source evidence.

Status: partial source-derived model.

### tests

#### Scoped evidence

Evidence: external wave32 rt_core receipt includes native-commands.json, exact named outcomes twice debug/twice release, raw status/log files, compiled production controls with byte restoration and paired syntax. Only named synthetic helpers execute; model_path/export and live CLI paths have representation/source evidence.

Coverage is limited to this fragment's reached branches; parent tests do not prove every scoped branch.

### invariant-and-cost

#### Scoped invariant and cost

Dedup/global-index map precedes decoder comparison; full patches compensate lost fields and XOR starts plus empty indices recover original sentence partition.

Let F frames, E entities, Q quote links, B cloned payload bytes, S=nsents and Z=r.empties.len(). Ordered maps add logarithmic lookups; starts can scan O(F^2*(Qmax+1)); decode_in position searches can be quadratic. decode_exact additionally scans the linear empties vector for each requested sentence: O(S*Z+S) time and O(S) output vector storage, independent of F. For S all-empty sentences, F=E=Q=0 and Z=S, yet contains performs S(S+1)/2 equality checks and emits S empty vectors. Deep frame/entity clones add B and recursion cost; no fixed capacity or allocation guarantee.

The parent bound is conservative; unrelated parent effects are excluded from this fragment.