---
title: "mlab-tests-vm-synthetic-parity — Mova code model"
description: "Mova code model of mlab/tests/vm.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/mlab/tests/vm.rs.groupant/synthetic-parity.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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# mlab-tests-vm-synthetic-parity

The groupant beside mlab/tests/vm.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:** [`mlab/tests/vm.rs`](https://github.com/ElamurAI/mova-free/blob/main/mlab/tests/vm.rs)
- **source SHA-256:** `752cb721b2bda77e…`
- **covers:** Seven bounded arithmetic, COW, loop, fallback, short-circuit, capture and string fixtures. (bytes 9417–10511)
- **part of:** [mlab-tests-vm](https://md.groupants.elamur.ai/free/en/mova/mlab/tests/vm.rs.groupant/)
- **repository folder:** [`mlab/tests/vm.rs.groupant/synthetic-parity.groupant`](https://github.com/ElamurAI/mova-free/tree/main/mlab/tests/vm.rs.groupant/synthetic-parity.groupant)
- **repository commit:** `855da7bd4a7b`

> **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** | symbolic source derived | [invariant](#invariant) |
| **descriptant** | present | [descriptant](#descriptant) |
| **invariant** | partial | [invariant](#invariant) |
| **tests** | executed 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) |
| `cow_fixture` | cow_fixture | partial source derived model | [cow_fixture](#cow-fixture) |
| `short_circuit_fixture` | short_circuit_fixture | partial source derived model | [short_circuit_fixture](#short-circuit-fixture) |
| `dynamic_fixture` | dynamic_fixture | partial source derived model | [dynamic_fixture](#dynamic-fixture) |
| `loop_fixture` | loop_fixture | partial source derived model | [loop_fixture](#loop-fixture) |

## Model text


### descriptant

#### mlab-tests-vm-synthetic-parity

Seven bounded arithmetic, COW, loop, fallback, short-circuit, capture and string fixtures.

##### Epoch 2026-10-31

Half-open source bytes [9417,10511); bound by parent source hash and scoped byte hash. Model covers only this fragment; parent composition explains joins.

### approximant

#### Scoped forward relation

For each fixture assert tree bytes equal fixed oracle and VM bytes equal tree; assert fallback/dyn counters on separate fixture.

##### Domain and gap

Source-generated states within resource limits. Categorical relation has no executable percent surrogate.

### invariant

#### Scoped invariant

A(1,2) stays2 while B(1,2) becomes9.

##### Cost

Seven finite programs and one counter fixture; largest matrix2x2 and range3..1. Includes repeated tree/VM construction, no timing claim.

### models

## Scoped typed relations

### behavior_complement

The fixed COW oracle excludes both matrices changing; short-circuit fixture excludes missing-function diagnostics; empty-loop fixture excludes printing99.

### reverse_reconstruction

Passing result identifies agreement on finite fixtures only; the two engines can share bugs outside them.

### cow_fixture

A(1,2) stays2 while B(1,2) becomes9.

### short_circuit_fixture

missing_wave30 is not called by false&& or true||.

### dynamic_fixture

String array indexing crosses DynEval; cell construction/clear cause fallback.

### loop_fixture

3:-1:1 sums6; [] executes no body.


### tests

#### Evidence scope

Parent selected tests: wave30_bounded_state_and_fallback, wave30_parse_runtime_and_output_state, wave30_synthetic_gate_fail_fast, vm_workspace_is_visible_after_run. This fragment shares parent syntax and finite checks; no separate test count or complete fragment coverage claim. Assertion-control association and unexecuted paths are in parent tests.md and source-test-map.json.