Distance groups.
No hidden tolerance.

RadialRadiusObservation {
  radialSystemRef,
  scopeRef, snapshotRef,
  subjectRef,
  coordinateFrameRef, unitRef,
  positionRef, positionOwnerRef,
  hubDescriptorRef,
  dx, dy,
  radiusSquared,
  radius,
  derivedFrom[],
  provenance: DERIVED,
  status,
  mutationAllowed: false
}

RadialRadiusBandDefinition {
  bandRef,
  radialSystemRef,
  scopeRef, snapshotRef,
  coordinateFrameRef, unitRef,
  minRadius, maxRadius,
  lowerInclusive, upperInclusive,
  sourceRef, sourceOwnerRef,
  provenance,
  status,
  mutationAllowed: false
}

RadialGroupDescriptor {
  groupRef,
  groupKind: EXACT_RADIUS_RING | RADIUS_BAND_GROUP,
  radialSystemRef,
  scopeRef, snapshotRef,
  coordinateFrameRef, unitRef,
  subjectRefs[],
  exactRadius,          // only exact ring
  radiusBandRef,        // only band group
  observedMinRadius,
  observedMaxRadius,
  sourceRadiusObservationRefs[],
  provenanceSet[],
  status,
  mutationAllowed: false
}

RadialRadiusBandAttachment {
  radialSystemSeedRef,
  hubDescriptorRef,
  radiusObservationSetRef,
  radiusBandSetRef,
  orbitalGroupSetRef,
  status,
  mutationAllowed: false
}

Compo23.00 RadialSystemSeed.radiusBandAttachmentRef
remains unchanged in-place.

Tests cover exact 23.00/23.01 lineage, zero-radius validity, Euclidean distance math, explicit interval boundaries, band gaps, ambiguity preservation, exact equal-radius rings, band-backed groups, immutable attachment, zero metrics, no angle/sector API and strict 23.03–23.04 ownership boundaries.

{
  "module": "Compo 23.02",
  "name": "radius_bands_and_orbital_groups",
  "version": "1.0-canonical",
  "canonical_main_title": "Radius bands and orbital groups",
  "topic": "23_РАДИАЛЬНЫЙ_БАЛАНС_И_ЦЕНТРАЛЬНЫЕ_СИСТЕМЫ",
  "scope": "EXACT_COMPO23_00_ROOT_AND_COMPO23_01_HUB_LINEAGE_DERIVED_NONNEGATIVE_RADII_EXPLICIT_RADIUS_BANDS_EXACT_RADIUS_RINGS_AND_NONSCORING_ORBITAL_GROUP_DESCRIPTORS_ONLY_WITHOUT_ANGLE_SECTORS_TOLERANCE_OR_SCORING",
  "main_topic_contract": {
    "topic_title": "Радиальный баланс и центральные системы",
    "topic_goal": "Формализует радиальные композиции: hub, rings, radius bands, angular sectors и распределение элементов вокруг центра.",
    "expected_output": "RadialGroupDescriptor, hub, rings, sectors",
    "planned_files": [
      "23.00 Radial system schema",
      "23.01 Hub/center detection",
      "23.02 Radius bands and orbital groups",
      "23.03 Angular spacing / sector occupancy",
      "23.04 Scoring, generator and tests"
    ]
  },
  "ownership": {
    "owner": "Compo23.02",
    "owns": [
      "RadialRadiusObservation",
      "RadialRadiusObservationSet",
      "RadialRadiusBandDefinition",
      "RadialRadiusBandPolicy",
      "RadialRadiusBandAssignment",
      "RadialRadiusBandSet",
      "RadialOrbitalGroupKind taxonomy",
      "RadialGroupDescriptor",
      "RadialOrbitalGroupSet",
      "RadialRadiusBandAttachment",
      "exact Euclidean distance-from-hub derivation without angle",
      "explicit interval-based radius-band assignment with ambiguity preservation",
      "exact equal-radius ring grouping without tolerance",
      "band-backed orbital grouping without quality interpretation",
      "identity/status/provenance rules for Topic23 radial-distance layer",
      "non-mutating correction request for radius/band/group lineage"
    ],
    "does_not_own": [
      "RadialSystemSchema / RadialSystemSeed identity — Compo23.00",
      "hub detection / hub truth — Compo23.01",
      "raw point geometry or foreign position identities — upstream geometry owners",
      "polar angle, angular spacing, angular sectors or sector occupancy — Compo23.03",
      "approximate-radius tolerance, fuzzy ring merge, target fit, scoring, MetricResult or generator — Compo23.04",
      "visual center of mass, moments and counterweights — Topic22",
      "mirror symmetry and symmetric-balance scoring — Topic21",
      "hierarchy, dominance, semantic importance, beautyScore or final-layout ranking",
      "foreign geometry/style/semantic mutation"
    ]
  },
  "consumes": [
    "exact Compo23.00 root bundle: RadialSystemSchema, RadialSystemSeed, RadialSubjectSet, RadialCoordinateFrameBinding, RadialPositionBinding[]",
    "exact Compo23.01 hub layer: RadialHubDescriptor + RadialHubAttachment",
    "owner-qualified RadialPositionObservation[] resolving exact 23.00 position bindings",
    "optional explicit RadialRadiusBandDefinition[] and bounded policies"
  ],
  "provides": [
    "RadialRadiusObservation[]",
    "RadialRadiusObservationSet",
    "RadialRadiusBandDefinition[]",
    "RadialRadiusBandAssignment[]",
    "RadialRadiusBandSet",
    "RadialGroupDescriptor[]",
    "RadialOrbitalGroupSet",
    "RadialRadiusBandAttachment"
  ],
  "owns_metrics": [],
  "independent_numeric_votes": 0,
  "status_semantics": {
    "OK": "valid exact local radius/band/group descriptor",
    "N_A": "missing/conflicting/ambiguous/not-applicable evidence; never numeric zero",
    "INVALID": "malformed or impossible record; never numeric zero"
  },
  "radius_rules": [
    "dx = subject.x - hub.x",
    "dy = subject.y - hub.y",
    "radiusSquared = dx^2 + dy^2",
    "radius = sqrt(radiusSquared)",
    "radius >= 0 and radius=0 is valid",
    "no angle is computed in 23.02"
  ],
  "band_policy": {
    "definitionMode": "EXPLICIT_INTERVALS_ONLY",
    "multipleMatchMode": "N_A_NO_GUESS",
    "gapMode": "UNASSIGNED_OK",
    "maxBands": [
      0,
      512
    ],
    "maxRadiusObservations": [
      1,
      4096
    ],
    "maxOrbitalGroups": [
      0,
      4096
    ],
    "overflow": "N_A_WITHOUT_TRUNCATION",
    "autoBandDiscovery": false,
    "autoTolerance": false,
    "autoApproximateRingMerge": false,
    "autoScoring": false
  },
  "orbital_group_kinds": [
    "EXACT_RADIUS_RING",
    "RADIUS_BAND_GROUP"
  ],
  "group_rules": [
    "EXACT_RADIUS_RING requires at least two subjects with exactly equal derived radiusSquared; no tolerance",
    "RADIUS_BAND_GROUP groups subjects with one unambiguous explicit band assignment",
    "a subject may appear in an exact-radius ring and a band-backed group because these are distinct descriptors, not independent scores",
    "singleton explicit band groups are valid descriptive groups",
    "unassigned band membership is valid and does not imply error or low quality",
    "ambiguous multiple-band membership is N_A and is never resolved by source order/confidence"
  ],
  "root_attachment_contract": {
    "radialSystemSeedRef": "exact Compo23.00 seed lineage",
    "hubDescriptorRef": "exact Compo23.01 hub descriptor identity",
    "radiusObservationSetRef": "exact Compo23.02 radius set identity",
    "radiusBandSetRef": "exact Compo23.02 band set identity",
    "orbitalGroupSetRef": "exact Compo23.02 group set identity",
    "rootMutation": false,
    "metricResultRefs": []
  },
  "firewalls": [
    "radius != angle",
    "radius != visual mass",
    "radius != hierarchy or importance",
    "radius=0 != N_A",
    "equal radius != equal shape/color/semantic role",
    "exact-radius ring != approximate ring",
    "radius band != quality band",
    "band midpoint is not inferred as target",
    "unassigned band != bad composition",
    "multiple band match -> N_A, not winner selection",
    "orbital group != angular sector",
    "orbital group != symmetry class",
    "descriptor != score",
    "N_A != 0",
    "INVALID != 0",
    "heuristic != law",
    "local != global",
    "geometry != interpretation",
    "correction request != foreign mutation"
  ],
  "topic23ProgressAfterThisModule": "3/5 local",
  "next_module": "Compo 23.03 — Angular spacing / sector occupancy",
  "hard_stop": "No 23.03–23.04 implementation in this file"
}