---
title: "modelcheck-syntax-parent-containment — Mova code model"
description: "Mova code model of tools/modelcheck/src/syntax.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/tools/modelcheck/src/syntax.rs.groupant/artifact-integrity.groupant/parent-containment.groupant/"
---
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# modelcheck-syntax-parent-containment

The groupant beside tools/modelcheck/src/syntax.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:** [`tools/modelcheck/src/syntax.rs`](https://github.com/ElamurAI/mova-free/blob/main/tools/modelcheck/src/syntax.rs)
- **source SHA-256:** `35c315cc9b581bea…`
- **covers:** Root identity and prior-parent interval safety (bytes 18297–19049)
- **part of:** [modelcheck-syntax-artifact-integrity](https://md.groupants.elamur.ai/free/en/mova/tools/modelcheck/src/syntax.rs.groupant/artifact-integrity.groupant/)
- **repository folder:** [`tools/modelcheck/src/syntax.rs.groupant/artifact-integrity.groupant/parent-containment.groupant`](https://github.com/ElamurAI/mova-free/tree/main/tools/modelcheck/src/syntax.rs.groupant/artifact-integrity.groupant/parent-containment.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 | [Forward](#forward) |
| **ast** | partial | `../../syntax.json` |
| **cost** | partial | [Cost](#cost) |
| **descriptant** | partial | [Descriptant](#descriptant) |
| **invariant** | partial | [Invariant](#invariant) |
| **tests** | partial | [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 relational specification | [behavior_complement](#behavior-complement) |
| `reverse_reconstruction` | reverse_reconstruction | partial relational specification | [reverse_reconstruction](#reverse-reconstruction) |
| `predecessor_index_safety` | predecessor_index_safety | partial relational specification | [predecessor_index_safety](#predecessor-index-safety) |
| `root_presence_distinction` | root_presence_distinction | partial relational specification | [root_presence_distinction](#root-presence-distinction) |
| `containment_transitivity` | containment_transitivity | partial relational specification | [containment_transitivity](#containment-transitivity) |
| `sibling_overlap_freedom` | sibling_overlap_freedom | partial relational specification | [sibling_overlap_freedom](#sibling-overlap-freedom) |

## Model text


Subject: current manifest source SHA and exact UTF-8 range [18297,19049). The observation is one completed scoped call with adequate resources; source-derived relations are partial specifications. Filesystem checks describe sequential reads, not an atomic snapshot.

### Forward

At index zero require explicit null parent, file/File labels and whole-source interval. Otherwise convert parent to usize, require parent<index, index previously accepted ranges and require containment before appending the current interval.

### Invariant

Each lookup ranges[parent] is bounded by strict predecessor admission. A child may share its parent's range; adjacency and non-overlap of siblings are not required.

### Cost

O(1) checks and one interval append per node, O(N) retained ranges. There is no recursive ancestry walk; predecessor order plus containment supplies local structural checks.

### Descriptant

Wave34, 2026-10-31: deeper scope retained under its existing parent without replacing historical views. Decode reuse was proposed before edits and checked against actual reference decoding; behavioral controls and repeated native receipts remain finite evidence. No numerical surrogate is justified for categorical validation outcomes; no percentage accuracy or complete semantic proof is claimed.

### Tests

Exact native test: syntax::wave34_tests::cached_decode_still_validates_source_and_nodes_and_measures_cost. Parent tests additionally exercise integration and failure order. Current evidence is in ../../wave34-evidence.md; old evidence remains explicitly historical in wave33-evidence.md at the source root.

### behavior_complement

Exclude root with missing/non-null parent or partial source interval; exclude nonroot self/future parent and children escaping their chosen parent. Exclusion concerns structural projections, not source semantic truth.

Assurance: source-derived partial relation; fixed source revision and stated scope. Oracle: syntax::wave34_tests::cached_decode_still_validates_source_and_nodes_and_measures_cost. Finite observations do not establish universal completeness.

### reverse_reconstruction

Given accepted child interval [a,b) at i, compatible parent IDs are all p<i whose stored [s,e) satisfies s<=a<=b<=e. Overlapping earlier nodes can make this antecedent nonunique.

Assurance: source-derived partial relation; fixed source revision and stated scope. Oracle: syntax::wave34_tests::cached_decode_still_validates_source_and_nodes_and_measures_cost. Finite observations do not establish universal completeness.

### predecessor_index_safety

Before iteration i, ranges.len=i. Strict p<i makes lookup safe. Weakening to p<=i admits self-parent and reaches a bounds panic before a clean diagnostic.

Assurance: source-derived partial relation; fixed source revision and stated scope. Oracle: syntax::wave34_tests::cached_decode_still_validates_source_and_nodes_and_measures_cost. Finite observations do not establish universal completeness.

### root_presence_distinction

An explicit parent:null is required at root; an omitted field fails even though Value indexing would also look null. Root labels and full extent are independent conjuncts.

Assurance: source-derived partial relation; fixed source revision and stated scope. Oracle: syntax::wave34_tests::cached_decode_still_validates_source_and_nodes_and_measures_cost. Finite observations do not establish universal completeness.

### containment_transitivity

On an accepted predecessor chain, repeated local containment implies every ancestor interval contains the child. This structural implication neither proves nearest-parent selection nor unique ancestry.

Assurance: source-derived partial relation; fixed source revision and stated scope. Oracle: syntax::wave34_tests::cached_decode_still_validates_source_and_nodes_and_measures_cost. Finite observations do not establish universal completeness.

### sibling_overlap_freedom

Two nodes may name one predecessor and overlap or have equal intervals. The checker does not impose partition coverage, adjacency or disjointness constraints.

Assurance: source-derived partial relation; fixed source revision and stated scope. Oracle: syntax::wave34_tests::cached_decode_still_validates_source_and_nodes_and_measures_cost. Finite observations do not establish universal completeness.