# QC Report — Physics/ Code Structure & Efficiency

## High Priority

| ID | Issue | Files | Fix |
|----|-------|-------|-----|
| H1 | `absDiff` duplicated 4x | DESIInvariant, H0ValveTest, ValveTestSuite, ClusterBHAnchors | Create Shared.lean, use `Int.abs` |
| H2 | `scale = 65536` duplicated 6x | UniversalBridge, DESIInvariant, DESIModelProjection, ValveTestSuite, ClusterBHAnchors, SuperpositionalBoundaryLayers | Single shared def |
| H3 | Duplicate theorems | AdjacentCoprimeClassification | 2 redundant (<`fibCond1==fibGcd1`, `ex3Cond1==ex3Gcd1`) |
| H4 | Dead `q16_div` | DESIModelProjection | Never called, remove |

## Medium Priority

| ID | Issue | Files | Fix |
|----|-------|-------|-----|
| M5 | Dead `DESIParam` | DESIInvariant | Remove or annotate |
| M6 | `q16Abs` = `Int.abs` | DESIModelProjection | Replace with stdlib |
| M7 | Dead `ModelParams`, `Residual`, `Verdict` structures | DESIModelProjection | 6 defs, no theorems exercise them |
| M8 | 25 separate theorems | AdjacentCoprimeClassification | Consolidate into `∧` chains per example |
| M9 | `q16_div` duplicated | UniversalBridge + DESIModelProjection | Share |

## Low Priority

| ID | Issue | Files | Fix |
|----|-------|-------|-----|
| L10 | h00/h01 share 4 Q16.16 lines | UniversalBridge | Factor helper |
| L11 | Q16.16 arithmetic inconsistency | SuperpositionalBoundaryLayers vs UniversalBridge | Unify |
| L12 | `SCALE` vs `scale` casing | SuperpositionalBoundaryLayers | Standardize |
| L13 | `rD` field naming | DESIInvariant | `rD` → `rd` |
| L14 | `rdDr1 = rdDr2 = 147` | DESIInvariant | Store as ×100 |

## Verdict

- 4 high-priority structural issues (duplication + dead code)
- 5 medium-priority issues (dead structures, consolidation)
- 5 low-priority issues (consistency, naming)
- All 8 files build cleanly (3529 jobs)
- No circular dependencies
- No efficiency bottlenecks in hot path