Elamur Groupantsworld-opchoice-candidates
The groupant beside world/src/opchoice.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 source model | forward |
| ast | partial | ../syntax.json |
| composition | partial source model | composition |
| cost | partial source model | cost |
| descriptant | partial source model | epoch-memory |
| invariant | partial source model | invariant |
| tests | partial source model | 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 |
|---|---|---|---|
world-opchoice-candidates-behavior-complement | behavior_complement | partial source model | behavior-complement |
world-opchoice-candidates-reverse-reconstruction | reverse_reconstruction | partial source model | reverse-reconstruction |
world-opchoice-candidates-intermediate-domain | constraint_relation | partial source model | intermediate-domain |
world-opchoice-candidates-arity-window | resource_boundary | partial source model | arity-window |
Model text
Op, Cand, question/features and candidate enumeration.
forward
Arithmetic is exact representable i64 Add/Sub/Mul/Div with nonnegative subtraction and integral division gates. Traverse x,y,OPS and append each first step then z,OPS second steps. Features combine arithmetic identity with external context.
invariant
Each retained intermediate is representable, even when hypothetical later cancellation could yield an in-range final result. Mention indices are distinct; commutative order is canonical.
cost
O(n^2) first-step work plus O(n^3) second-step work restricted to n=3..5; O(C) candidate space. Feature cost depends on context lengths/cache lookups; kind cache can grow by unique word/POS.
composition
Candidate enumeration feeds features and first-max scoring. Learner interns the same feature occurrences, preserves candidate order and updates toward the first highest-scoring gold-valued candidate. Text extraction and lexical environment must be fixed. top uses lexical expression ties unlike choose; parent ranking cannot silently substitute one for the other.
epoch-memory
2026-10-30: i128 oracle exposed unchecked arithmetic overflow. Checked operations now omit unrepresentable candidates, including MIN/-1 division; score and training overflow remain bounded-domain assumptions. Dense learner history and first-tie tests preserve existing behavior.
checks
See ../tests.md and native opchoice::wave8_models tests. Models are source-derived partial relations, with finite evidence rather than general proof. Syntax projection excludes macro expansion, name resolution and inferred types. No executable approximant: exact gates and categorical choices have no justified percentage metric here.
behavior-complement
In candidate-output universe, second steps at n=6, reversed commutative duplicates and overflowing intermediates are absent. Full final-expression representability alone is insufficient.
reverse-reconstruction
For fixed mentions and value v, retain all enumerated canonical expressions yielding v. Add/Mul reverse domain excludes redundant reversed index order; numeric values cannot recover lexical context.
intermediate-domain
Invalid first operation omits both the first candidate and all extensions. The independent oracle evaluates in i128 then converts each intermediate separately.
arity-window
Adding an unrelated sixth mention removes all two-step candidates. Parent mention extraction must preserve count; distractors can reduce reachability rather than only add choices.
This page in Markdown → https://md.groupants.elamur.ai/free/en/mova/world/src/opchoice.rs.groupant/candidates.groupant/