Mathematical Foundations
Appendix K
Aa
This appendix does not prove new theorems. It identifies exactly which theorems from model theory, sheaf theory, and type theory underpin the Third Mode's guarantees—and states what each guarantee does not promise.
The proposed discipline joins familiar mathematics to explicit design obligations. Those obligations require their own implementation evidence.
The Borrowed Machinery
The main sources of the established guarantees are existing mathematics. The cost framework is a separate proposal; Appendix L distinguishes further finite calculations from unfinished constructions:
| Guarantee | Underlying Theorem | Canonical Source |
|---|---|---|
| Preservation of old-language consequences | Conservative extension | Shoenfield, Mathematical Logic (1967), §4.6 |
| Local-to-global coherence | Sheaf gluing condition | Mac Lane & Moerdijk, Sheaves in Geometry and Logic (1992), Ch. II |
| Substitution under equivalence | Transport along paths | HoTT Book (2013), §2.3 |
| Verification expenditures | A21 cost categories and declared checking schedules | Chapter 19; no general monotonicity theorem |
The proposed specification draws on that infrastructure. Existing systems already supply proofs, provenance, contracts and structured failures in various settings; this companion brings their obligations into one account of admission and subsequent use. Its interfaces require implementation evidence, and its unfinished constructions cannot borrow guarantees from the established results beside them.
What This Appendix Provides
For each result used by a later construction, we state:
- The theorem — What the mathematics guarantees
- The operational consequence — What this means for system behavior
- The failure mode — What would constitute a violation
- The anchor — Where the main text invokes this machinery
For readers who want full proofs, the canonical sources are cited. For readers who want to understand how the proofs translate to system design, the operational consequences are the payload.
K.1 Conservative Extension Safety
Informal claim: Under the stated model-expansion hypothesis, adding the predicate creates no new old-language theorems.
Let and be classical first-order theories, with and , using a sound and complete proof system. Suppose every model of has a -expansion satisfying . Then the extension is deductively conservative:
For every -sentence ,
That is: the new predicate does not create new theorems in the old language.
Proof sketch (model-theoretic):
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Let be a model of the original theory.
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Extension: We must show extends to . The expansion hypothesis supplies an interpretation of satisfying the new constraints while leaving the old structure unchanged. Freshness of the symbol alone does not supply that interpretation.
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Conservativity: Suppose for a -sentence . By soundness, holds in all models of . In particular, it holds in all extensions of models of . Since is a -sentence, its truth depends only on the -reduct. Therefore holds in all models of . By completeness, .
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The converse is immediate: if , then every model of is an extension of some model of , so holds.
Failure mode: The extension fails to be conservative if the new constraints entail -sentences not provable from alone. Example: adding with constraint where is an existing predicate creates a conservative extension. Adding with constraint and forces , which is non-conservative if was not previously provable.
Operational consequence: When admission claims to preserve the old theory, A17/A29 require the corresponding conservativity argument. A separately authorized revision must identify what it changes. A verified old-language consequence of the new theory that fails in a model of the old theory refutes deductive conservativity. A model that cannot be expanded refutes the stronger expansion condition used above; by itself it is not that sentence-level counterexample. An inconclusive check establishes neither failure nor safety.
Anchor: A17b (Conservative Extension). This theorem and its proof are developed in full in Chapter 16.
K.1.1 Verification Strategies
Conservative extension is a semantic property. In general, checking it is undecidable. In practice, we deploy a hierarchy of verification strategies, each with known tradeoffs.
Modes
| Method | What it can establish | Boundary |
|---|---|---|
| Syntactic sufficient condition | Conservativity for a proved class, such as explicit definitions with the required freshness conditions | A formula outside that class need not be non-conservative |
| SAT/SMT encoding | The obligation actually encoded, in a supported fragment | Solver success on a different satisfiability question is not a conservativity proof |
| Model sampling | A checked counterexample, when the relevant old-language consequence is supplied | Failure to find one is not a general guarantee |
| Proof assistant | The formalized proposition under its declared hypotheses and axioms | Proof checking is not a complete procedure for discovering a proof; goals may remain unfinished |
Artifacts
A verification attempt produces one of:
ConservativityProof: A formal proof object (possibly machine-checked) establishing the extension is conservative.Countermodel: A model and a -sentence such that but . This is a concrete witness of non-conservativity.UnsatCore: An inconsistent subset returned for a declared encoding, such as new assumptions together with the negation of a proposed consequence. Minimality requires a separate check; an unsatisfiable core alone does not establish non-conservativity.Timeout: The verification budget was exhausted. The system treats this as "unknown" and may escalate to a higher mode or reject the predicate pending manual review.
Complexity and Limits
The complexity belongs to the encoded obligation. In a finite propositional language, the model-expansion test asks whether every old valuation satisfying admits new values satisfying :
This is not the single satisfiability test whose complexity the earlier table reported. Equality and linear-arithmetic encodings likewise require the actual projection or consequence conditions; union-find or linear programming does not solve every conservativity problem bearing those labels. The former generic complexity table and claim of a semi-decision procedure for arbitrary first-order conservativity are withdrawn. A tractable fragment must name its permitted formulas and the test being implemented.
The Coherence Budget and an Inconclusive Check
A21 limits how much checking the implementation undertakes. It does not convert an approximate result or timeout into a proof. A syntactic sufficient condition can establish safety when its hypotheses hold; a heuristic screen can guide investigation without certifying the extension.
Expensive verification may be deferred, but a pending proposal must not acquire certified standing merely because it has entered a queue. Risk-tiered policies can select stronger checks or decline a use. Each outcome must retain the attempted obligation, method, budget and result, including an explicit unknown. The budget governs the work purchased; it cannot enlarge what that work established.
K.2 Gluing Correctness
Informal claim: If local claims agree on overlaps, the sheaf condition guarantees a unique global claim.
Let be a sheaf on the context site . Let be a cover of .
If sections satisfy the matching condition:
then there exists a unique such that for all .
Proof sketch (equalizer diagram):
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The sheaf condition states that is the equalizer of:
where restricts the -th component to , and restricts the -th component.
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A family is in the equalizer iff , i.e., for all .
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Existence: The matching condition says is in the equalizer. Therefore there exists that maps to under restriction.
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Uniqueness: The equalizer is a limit; the map is injective (this is the locality condition). Therefore is unique.
Failure mode: If the matching condition fails (some ), the family is not in the equalizer, and no global section amalgamates this family. The failure is localized to the specific overlap(s) where disagreement occurs.
Operational consequence: An implementation of glue needs effective maps, comparison procedures and a construction for the specified sheaf. It can then return the amalgamation or established unequal restrictions. If checking remains incomplete, it must say so. The abstract existence theorem does not supply a terminating algorithm for every sheaf.
Anchor: A13 (Sheaf Condition). This theorem and its proof are developed in full in Chapter 11.
K.3 Scoped Transport Safety
Informal claim: Transporting a property along a witnessed equivalence preserves truth within the declared scope.
Let be a witnessed equivalence with scope . Let be a transportable property. Let be a context in the equivalence's scope.
Suppose the supplied transport includes a validated proof map in the declared logical interpretation. If holds with proof in context , then holds with proof there.
The proposed interface rejects use of this certificate outside S. That rule does not prove that another certificate or independently defined transport is impossible there.
Proof sketch:
Applying the validated map to gives a proof of . Statistical or attested support requires its own interpretation and cannot acquire this proof guarantee merely by being called a witness.
Operational consequence: The proposed transport operation checks the certificate, scope, property footprint and required maps. Established use outside the certificate’s scope produces ScopeViolation; an unfinished scope check produces Inconclusive. Neither certifies the requested substitution. Its receipt binds those inputs and the resulting claim. Whether a recipient can validate it depends on the evidence and checking procedure supplied; the receipt’s existence is not its own verification.
Anchor: A10 (Witnessed Sameness), A16 (Transport Discipline), A30 (Scoped Equivalence). This theorem and its proof are developed in full in Chapter 14.
K.4 Coherence Costs and the Withdrawn Ordering
Corrected claim: Cover refinement alone does not order verification costs.
The former monotonicity theorem used the number of nonempty overlaps between distinct cover members as its cost. On the discrete space , the cover has one such overlap. Its singleton refinement has none. The asserted inequality is false even under that unit-cost convention.
The proof's proposed injection from coarse overlap checks to fine overlap checks does not exist in this example. A refinement requires each fine member to factor through a coarse member; it does not require every old comparison to survive as a distinct new comparison. The theorem, its equality claim and the inference that refinement necessarily increases verification cost are withdrawn.
Operational consequence: A21 remains a framework for declaring compile-time, run-time and organizational expenditures, the checks to be performed, and the actions available when a budget binds. Comparisons must specify the information and obligations retained, checking frequencies and per-check costs. Keeping an old checking schedule and adding nonnegative charges cannot reduce its sum; replacing that schedule is a different question, which refinement alone does not settle.
Anchor: A21 (Coherence Cost Model). Chapter 19 develops the counterexample and the surviving budget framework. The correction history is recorded outside the narrative in the edition's correction record.
K.5 What These Results Guarantee
The preceding sections distinguish conditional mathematical guarantees from the cost accounting needed to choose a checking regime:
| Result | Guarantee |
|---|---|
| Conservative Extension Safety | The stated extension creates no new old-language theorems |
| Gluing Correctness | Exact matching in the specified sheaf gives a unique amalgamation |
| Scoped Transport Safety | Validated transport carries the declared evidence within its scope |
| Coherence Cost Model (A21) | Declares expenditures and budgets; no universal cost ordering |
What they do NOT guarantee:
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Completeness: The Third Mode does not guarantee that every true statement can be proved. A particular implementation must establish the admission conditions it claims to enforce.
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Decidability: Checking the matching condition may be undecidable for some presheaves. The Third Mode specifies what must be checked, not that checking is always tractable.
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Convergence: Multiple agents proposing predicates may not converge to a shared vocabulary. The Third Mode provides discipline, not consensus.
K.6 Formal Dependencies
The results depend on the following formal machinery:
| Result | Dependencies |
|---|---|
| Conservative Extension | Model theory, completeness for the ambient logic |
| Gluing Correctness | Sheaf theory, equalizer definition |
| Scoped Transport Safety | Equivalence structure, transport maps |
| Coherence Cost Model | Declared work, checking schedule and cost estimates; refinement alone is insufficient |
For full proofs, consult:
- Shoenfield (1967) for conservativity in classical logic
- Mac Lane & Moerdijk (1992) for sheaf theory
- HoTT Book (2013) for transport along equivalences
- Grothendieck (SGA4) for site theory
The proposed contribution is to connect these results to operational obligations: which artifact establishes which claim, and what a recipient can do when the required check fails or remains incomplete. Specifying that connection is not evidence that it has been implemented.
K.7 Formal Mini-Spine: The Obstruction Localization Theorem
The following definitions locate pairwise disagreement in a specified presheaf. The result separates that failure from uniqueness under separation and existence under the sheaf condition.
K.7.1 Definitions
A context category is a category where:
- Objects are contexts —each representing a view with a signature (vocabulary), constraints, and absence policy.
- Morphisms are refinements: is a more specific context than (e.g., "FDA regulatory view" refines "US legal view").
- Composition is associative; identities exist.
A Grothendieck topology on assigns to each object a collection of covering sieves. A sieve on is a subfunctor of ; it is covering if it is in .
For our purposes, we use the simpler notion of a covering family: a collection such that the sieve it generates is in .
The pair is a site.
A presheaf on is a contravariant functor .
- For each context , is the set of local sections (the local data supplied by the model).
- For each morphism , is the restriction map (how a claim in appears when viewed from the more specific context ).
Let be a covering family of . A matching family for a presheaf is a collection of sections such that for all :
where is the pullback (the "overlap" context where both and apply).
A presheaf is a sheaf if for every covering family and every matching family , there exists a unique section such that for all .
The unique is called the gluing of the family .
If is not a matching family (some ), we say there is an obstruction to gluing. Define:
This is the set of disagreeing pairs.
K.7.2 Theorem Statement
Let be a presheaf on a site with the pullbacks used below. Let be a covering family and a collection of local sections.
Either:
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is a matching family. If is separated for this cover, there exists at most one restricting to all . For an arbitrary presheaf, matching alone gives neither existence nor uniqueness, or
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is not a matching family, in which case , and this set exactly identifies the pairs where the obstruction occurs.
Moreover, if is a sheaf, case (1) guarantees existence and uniqueness of the gluing.
K.7.3 Proof
We prove each part.
Part 1: Separation implies at-most-one gluing.
Suppose is a matching family and both satisfy and for all .
Consider the restriction diagram:
where , and are the restriction maps to overlaps.
By assumption, .
The map is injective for separated presheaves (and hence for sheaves). This separation property is precisely what distinguishes separated presheaves from arbitrary presheaves; for a sheaf, it holds by definition. Under the stated separation hypothesis, injectivity gives . Without that hypothesis this step is unavailable.
Part 2: Non-matching implies nonempty obstruction set.
Suppose is not a matching family. Then by definition, there exist such that . Hence , so .
Part 3: Obstruction set exactly identifies disagreements.
By construction, if and only if . The set contains no spurious pairs and omits no actual disagreements.
Part 4: Sheaf implies existence.
If is a sheaf and is a matching family, the sheaf condition guarantees existence of with . Combined with Part 1, the gluing is unique.
K.7.4 Operational Consequence
The Obstruction Localization Theorem justifies the ObstructionWitness artifact:
ObstructionWitness {
cover: [U_i],
local_sections: {U_i: s_i},
disagreeing_pairs: Obs({s_i}),
specific_conflicts: [(i, j, s_i|_{overlap}, s_j|_{overlap})]
}
When the supplied sections disagree on an overlap, this specification calls for more than a generic "conflict" error. It returns a structured object that names:
- Which contexts were involved
- What claims each context made
- Which pairs disagreed
- What the disagreeing values were
For a finite cover with effective restriction maps and decidable equality, these disagreeing pairs can be computed. Returning them in this format is a design obligation motivated by the calculation. Abstract sheaf theory alone supplies no termination bound, and a non-sheaf can fail to glue a matching family even when this disagreement set is empty.
The witness substantiates this particular failure: “contexts and disagree on the overlap , with these specific values.” Other failures—missing information, undecidable comparison or a budget exhausted before checking—need their own status. An empty disagreement list cannot stand in for a successful gluing.
Chapter 11 develops what these distinct outcomes permit a recipient to report. The complete obstruction-localization statement and proof are given here; its gluing-correctness proof remains in Chapter 11 and §K.2.
K.8 What the Machine Checks
A checked declaration establishes its conclusion under its actual hypotheses. It does not verify a chapter, an interpretation of a data source, or the operation of an institution. The definitions, written arguments and proposed interfaces in this companion retain those distinct statuses. Appendix L's H¹ classification and invention monad are not established by the projects below.
The September 11, 2026 audit compiled the unchanged selected source targets with Lean 4.28.0. Mathlib-dependent targets used the recorded revision 8f9d9cff6bd728b17a24e163c9402775d9e6a365. The declaration inventory records imports and hypotheses separately from kernel axioms: #print axioms does not reveal that a theorem assumes its substantive conclusion.
| Project and source module | Exact declaration(s) | Checked conclusion and boundary |
|---|---|---|
SCPI, Torsor | filled_simplex_trivial_H1; nontrivialCircularCocycle_not_coboundary | The specified three Z/2 transitions are a coboundary under the filled-triangle equation; the specified circular example is not. These are not arbitrary-site or institutional classifications. |
SCPI, Counterexample; AssumptionD | no_compatible_global_predicate; assumption_D_finite | The fixed local predicates disagree; pointwise-agreeing predicates on a finite indexed subset cover glue uniquely. The underlying domain need not be finite. |
SCPI, Conservativity; Beth | conservativity_descent; beth_for_sites | The first obtains its conclusion from h_local; the second manipulates proposition-level scaffolding. Compilation supplies no general semantic conservativity or Beth theorem. |
SHEAF, Algorithm | algorithm1_correct | Zero back-edge residuals characterize the given cochain's coboundary status with an already supplied TreePropagation satisfying the tree equations. No BFS construction or all-group vanishing is proved. |
SHEAF, Monotonicity | h1_dim_nondecreasing_edge_addition | A numerical inequality under explicit edge/rank-count assumptions. It concerns a different operation from A21's arbitrary cover refinement. |
CompositionDoctrine, RankMonotonicity; Characterization | rank_column_restriction_le; disclosure_characterization | Rank does not increase on the specified injective column restriction. Numerical uniqueness holds on a ReducibleDoctrine with its stipulated reduction and characterization axioms. Application to a concrete semantic system requires that model identification. |
CompositionDoctrine, LocalCertificationSQ | csq_query_lower_bound_concrete | The finite counting inequality follows under the declared nonnegative weights, union-bound and identification assumptions. Correspondence to an empirical query process is separate. |
InterpolantEnvelope, Finite, GoldenV02, ClaimFlow, Generalization, AssuranceLinker | full_package_safe; truncation_preserves_safety; no_free_precedent; adoption_and_applicability_are_separate_premises; capital_conservation | Finite modeled safety and claim/authority rules. Some conclusions project assumed fields: capital_conservation uses the portfolio's conserved premise. These do not prove custody, collectibility, capture or enforceability. |
AccountabilityDescent, AuthorityCycle; QueryFiber | triangle_holonomy_eq_one_of_globalGauge; not_queryAnswerable_of_erasureCertificate | A gauge implies the group identity; identical observations with different answers prevent answerability through those observations alone. Event occurrence and actual institutional authority are not established. |
The fresh compilation covered the SCPI and SHEAF roots, the three specified CompositionDoctrine targets, and the InterpolantEnvelope and AccountabilityDescent roots. All seven targets passed. The inspected declarations used no sorryAx or authored kernel axiom; recorded dependencies were the standard propext, Classical.choice and Quot.sound where needed. The whole CompositionDoctrine root was not rebuilt: its unrelated Locality and RealizationSheafPhase2 modules retain two unfinished declarations. They do not enter the selected Characterization, RankMonotonicity or LocalCertificationSQ targets.
Three other evidence boundaries matter to the public research summaries:
- Signed incidence: the archived completed source proves
CorrespondenceTheorem.signed_incidence_det_in_unit. The accompanyingfee_field_independentconcludesTrue; it is a placeholder, not a rank-equality theorem. Field independence follows by the written nonzero-minor argument from total unimodularity. This standalone archived source is not imported by the SHEAF root and was inspected, not freshly compiled in this audit. - Repair-basis count: the corrected product of component sizes is supported by its written argument. No matching machine declaration was located. The checked rank and leverage identities do not count those bases.
- Tarski Coherence: the unchanged locked evidence covers
TarskiCoherence.QuiverGadget.hodgeTarski_characterizationunder its self-loop-free quiver and complete-lattice/Galois-connection hypotheses. Its 43-result record is a specified historical scope, not a count of every later helper. That project was not rebuilt in this audit; its existing source and build records are retained.
The accompanying publication correction record preserves the full source/import/declaration map and build results in publication/corrections/2026-09-11-proof-evidence/. Neither successful compilation nor the absence of machine checking decides the validity or importance of a written proof. The boundary is what the result says, what it assumes, and which later claim actually uses it.