AAT Part VI
Repair and Dynamics
Repair, synthesis, operation paths, homotopy, and diagram filling describe how architecture objects move. Each movement is read through selected measures and explicit side-effect boundaries.
Repair and synthesis
A `RepairStep` is an operation intended to reduce a selected obstruction measure. A repair theorem must state which witness universe decreases, which invariant is preserved, which axes are not claimed to improve, and where side effects may appear.
RepairStep
= source
+ target
+ selected obstruction measure
+ decrease theorem boundary
+ side-effect boundary
Synthesis constructs an architecture object or operation sequence satisfying constraints. A no-solution result needs a finite complete search universe, explicit constraint language, decision procedure, and coverage boundary; solver failure alone is not a mathematical certificate.
Complexity transfer
`ComplexityTransfer` captures the case where complexity or an obstruction appears to disappear only because it moved to another axis. AAT requires selected evidence, selected target, residual gap, and non-conclusion boundary before calling an obstruction eliminated.
A repair package may prove that one selected measure decreases. It does not prove that all signature axes are non-increasing unless that theorem boundary says so.
Repair theorem schema
A repair theorem is intentionally narrow. It states that a selected measure decreases or a selected witness disappears, while preserving named invariants and recording all axes whose behavior is not concluded.
RepairStep X Y
+ selected witness universe W
+ obstruction measure m
+ invariant family I
+ side-effect boundary E
->
m(Y) < m(X)
+ I is preserved within B
+ non-conclusions for untracked axes
Synthesis has a stronger burden. A generated candidate needs satisfaction evidence, while a no-solution claim needs a finite complete candidate universe and a checked decision procedure.
| Claim | Current Lean status | Boundary | Non-conclusion | Source |
|---|---|---|---|---|
| Repair step decreases selected measure | `defined only` / `proved` for bounded packages | Selected witness universe, obstruction measure, preserved invariant, and side-effect boundary. | Does not prove all signature axes are non-increasing. | Lean theorem index, repair entries. |
| Repair synthesis / no-solution soundness | `defined only` / `proved` for bounded schema accessors | Finite complete candidate universe, explicit constraints, decision procedure, and coverage boundary. | Solver failure alone is not a mathematical no-solution certificate. | Lean theorem index and proof-obligation ledger. |
| Path homotopy and diagram filling | `defined only` / `proved` for selected observation-invariance bridges | Selected generators, selected observations, and diagram universe. | Does not prove global semantic completeness or preservation of every observation axis. | Lean theorem index, Chapter 8-9 entrypoints. |
Signature trajectory
A repair is best read as a movement through signature space. The theorem may prove a decrease on one selected coordinate, while the trajectory records unchanged, transferred, introduced, or unmeasured coordinates elsewhere.
ArchitecturePath X0 Xn
+ selected repair steps
+ signature coordinates at each step
+ transferred or residual witnesses
+ non-conclusions
-> bounded repair reading
This trajectory view is what prevents a local repair theorem from becoming a total quality claim.
Paths and filling
`ArchitecturePath` is an operation sequence. Two paths can reach the same feature outcome while preserving different invariants, introducing different witnesses, or tracing different signature trajectories.
`PathHomotopy` compares paths under selected generators and an observation model. Semantic diagram filling supplies evidence that different implementation paths give the same observation; a failed equality can become a `NonFillabilityWitness`.
Obs(lhs) != Obs(rhs)
-> NonFillabilityWitness D
No-solution boundary
Synthesis can produce a candidate object, a repair sequence, or a no-solution certificate. The last case is the strongest and therefore needs the clearest boundary: a finite complete search universe, an explicit constraint language, a decision procedure, refuted candidate cases, and coverage assumptions.
Solver failure alone is not a mathematical certificate. It may be a tooling result, a timeout, or an unsupported-construct boundary. AAT keeps those cases separate from a proved no-solution theorem.
finite complete candidate universe
+ explicit constraints
+ decision procedure
+ refuted candidates
+ coverage boundary
-> no selected solution
Path example
Two coupon implementations can reach the same visible checkout result while following different paths: one introduces a declared discount interface first, then adds the feature; the other adds a direct adapter call and later repairs the static graph. The final feature may look equivalent while the witness history and signature trajectory differ.
- Path invariant A property preserved at every step of the selected operation sequence.
- Homotopy generator A permitted rewrite between operation fragments under a selected observation model.
- Non-fillability witness Evidence that two paths fail to agree on the selected observation.
Lean status
Repair steps, repair synthesis, architecture paths, homotopy skeletons, diagram fillers, non-fillability witnesses, and selected observation-invariance bridges are tracked in the Lean theorem index. The public reading is bounded: global semantic completeness and all-axis improvement are not current conclusions.
A repair theorem may prove a selected measure decreases. It does not prove total architecture improvement unless the theorem boundary explicitly covers every relevant axis.