---
title: "world-school-tree-settlement — Mova code model"
description: "Mova code model of world/src/school_tree.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/world/src/school_tree.rs.groupant/settlement.groupant/"
---
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# world-school-tree-settlement

The groupant beside world/src/school_tree.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:** [`world/src/school_tree.rs`](https://github.com/ElamurAI/mova-free/blob/main/world/src/school_tree.rs)
- **source SHA-256:** `ca5ada75804e1d2e…`
- **covers:** Contiguous source scope; syntax is shared with source-bound parent. (bytes 39455–46106)
- **part of:** [world-school-tree](https://md.groupants.elamur.ai/free/en/mova/world/src/school_tree.rs.groupant/)
- **repository folder:** [`world/src/school_tree.rs.groupant/settlement.groupant`](https://github.com/ElamurAI/mova-free/tree/main/world/src/school_tree.rs.groupant/settlement.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 source model | [forward](#forward) |
| **ast** | partial | `../syntax.json` |
| **composition** | partial source model | [composition](#composition) |
| **cost** | partial source model | [cost](#cost) |
| **descriptant** | partial source model | [epoch-memory](#epoch-memory) |
| **invariant** | partial source model | [invariant](#invariant) |
| **tests** | partial source model | [checks](#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-school-tree-settlement-behavior-complement` | behavior_complement | partial source model | [behavior-complement](#behavior-complement) |
| `world-school-tree-settlement-reverse-reconstruction` | reverse_reconstruction | partial source model | [reverse-reconstruction](#reverse-reconstruction) |
| `world-school-tree-settlement-relation-fiber` | reverse_reconstruction | partial source model | [relation-fiber](#relation-fiber) |

## Model text

### forward

Resolve pending affine relations until no missing actor is added, settle numbers, carry things, convert prices to pay.

### invariant

First actor holding wins; relation closure does not overwrite present actor. Thing/price passes ordered.

### cost

Cloned relations and linear holdings scans; finite missing-actor additions on safe domain.

### composition

Source-bound parent supplies exact shared state and dependency assumptions. Independently projected fragments do not prove their wiring.

### epoch-memory

Initial 2026-10-30 scope. Preserve unknown lexical, data and effect semantics. Source inspection and executed bounded helpers remain distinct.

### checks

Nine native tests in wave9_models (five prules, four school_tree), repeated twice per debug/release profile, plus compiled production mutants; see evidence.md in the file parent. Binomial word oracle n<=12, gate finite grid, supplied-head graph universe 6^4, feature boundaries and reverse fibers. No real learning/data-loading or parser-to-Reading run. Prospective math recorded before implementation; large-n old-code failure precedes repair.

### domain

Fix source revision, external dependency outputs, configuration and sufficient resources. Observe one terminating call or explicitly bounded trace. Arithmetic domains exclude overflow except named refusal tests. Specialized relations are source-derived partial models unless a finite oracle is explicitly named. No unrestricted reverse solver is implemented.

### behavior-complement

Safe relation closure cannot overwrite an already-present actor or resolve an entirely unseeded component. Thing carry needs an actor-specific or global prior thing. A nonempty price map does not convert unmatched events. These inner absent transitions follow inspected guards; full fold remains unexecuted.


### reverse-reconstruction

Retain every integer predecessor satisfying the affine truncation equation, not merely code's one reverse representative. Thing carry erases which empty/pronominal placeholder existed. Price conversion erases original verb, receiver and modifiers; retain all prior matched-item events producing the actor and multiplied amount, subject to safe products.


### relation-fiber

Fix safe integers p,q,d with q!=0: a=trunc(b*p/q)+d. An observed a may have multiple b. Reverse code computes trunc((a-d)*q/p) when p!=0, choosing one candidate rather than full converse. For p=1,q=2,d=0,a=1, b=2 and3 are compatible; code picks2. Domain excludes overflow and zero denominators. This is inspected arithmetic, not a tested complete Reading inverse.