Elamur Groupantsmodelcheck-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
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 |
| ast | partial | ../../syntax.json |
| cost | partial | Cost |
| descriptant | partial | Descriptant |
| invariant | partial | Invariant |
| tests | partial | 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 |
reverse_reconstruction | reverse_reconstruction | partial relational specification | reverse_reconstruction |
predecessor_index_safety | predecessor_index_safety | partial relational specification | predecessor_index_safety |
root_presence_distinction | root_presence_distinction | partial relational specification | root_presence_distinction |
containment_transitivity | containment_transitivity | partial relational specification | containment_transitivity |
sibling_overlap_freedom | sibling_overlap_freedom | partial relational specification | 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.
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