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Section 9 — One-page interface contract \(Paper 2 → Paper 1\)

Research · Research Note

Section 9 — One-page interface contract \(Paper 2 → Paper 1\)

This file is the single copy-paste certificate sheet Paper 2 should output once the reduction is complete.
It is designed so Paper 1 can be invoked with no interpretation.

Machine-parsable payload conventions for the same objects (graphs, words, logs) are fixed in 09D_CERTIFICATE_SCHEMA.md.

For the dependency arrows and the theorem-versus-certification separation (so no symbol drift occurs across sections), see 13_LOGICAL_ARROWS_AND_CERTIFICATION_SEPARATION.md.

If you run the end-to-end runner paper2_reduction/tools/run_pipeline.py on a payload directory, it writes a machine-produced contract_generated.md alongside the JSON payloads. That file is a concrete instantiation of the fields in this contract sheet, referencing the exact artifact filenames.

The same runner also writes verification.json and verification_report.md (see Section 11) unless verification is skipped. These are finite regression checks for the PA bridge constants and the bounded closing constant.

The fields below are the only quantities Paper 1 uses.


9.1 Certificate sheet (fill-in values)

ItemSymbol / ValueHow to obtain (finite / checkable)Used by Paper 1
Reduced base system\((\Sigma_{\mathcal D},\sigma)\), presentation graph \(G\)finite presentation from descriptor reductionscope + locality
Descriptor size\(d=|\mathcal D|\)count statesconstants
Template set\(\mathcal T=\{T_1,\dots,T_m\}\)explicit finite listFTG
Template count\(m\)count templatesFTG
Positive entry bounds\(\underline a,\overline a\)min/max over positive entriesall constants
Nucleus periodic word\(w_*\) (length \(L:=|w_*|\))chosen candidate cyclenucleus
Nucleus product\(P_*:=P(w_*)\)multiply templates along \(w_*\)Doeblin block
Core support graph\(G(P_*)\)edge \(i\to j\) iff \((P_*)_{j,i}>0\)primitivity
Primitivity exponent\(k_0\)power test / Wielandt bound on \(G(P_*)\)Doeblin block
Doeblin block word\(u_*:=w_*^{k_0}\) (length \(|u_*|=Lk_0\))definitionDoeblin return block
Doeblin block matrix\(B_*:=P(u_*)=P_*^{k_0}>0\)numeric powercontraction
Entry bounds on \(B_*\)\(\varepsilon_*:=\min(B_*)_{ij}\), \(\overline M_*:=\max(B_*)_{ij}\)direct min/max or coarse FTG boundHilbert diameter
Hilbert diameter bound\(\Delta_*\) or coarse bound via \(\varepsilon_*,\overline M_*\)standard formulaBirkhoff
Contraction factor\(\tau_*:=\tanh(\Delta_*/4)\)standardBirkhoff

9.2 Breakthrough certificate (PA)

If Paper 2 certifies periodic approximation at the minimum (PA) via Theorem 8.3, record:

ItemSymbol / ValueHow to obtain (finite / checkable)Used by Paper 1
Positive bridge word\(v\)take \(v:=u_*\) so \(P(v)=B_*>0\)PA
Bridge matrix\(B:=P(v)>0\)multiplyPA
Doeblin constants\(\beta_{\min}:=\min B_{ij}\), \(\beta_{\max}:=\max B_{ij}\)direct min/max or coarse boundquasi-multiplicativity
Mixing/closing bound\(L_0\)compute mixing time on \(G\) (boolean powers)bounded closing
Statement“(PA) holds by Theorem 8.3 with \((v,B,\beta_{\min},\beta_{\max},L_0)\)”finite verificationPA ⇒ PO route

The machine checklist for \(L_0\), \(k_0\), and FTG-compatible bounds is in 08A_PA_CERTIFICATE_CHECKLIST.md.


9.3 Uniqueness certificate on periodic orbits (SCG)

Paper 1 treats SCG as a certificate input.
SCG must be packaged as a machine-verifiable object per 09A_SCG_CERTIFICATE_CHECKLIST.md.

Before claiming SCG, run the obstruction test and regime classification in:

  • 09C_SCG_OBSTRUCTION_AND_REGIMES.md.

Record the following fields:

ItemSymbol / ValueHow to obtain (finite / checkable)Used by Paper 1
Nucleus periodic word\(w_*\)same \(w_*\) as aboveidentity
Claimed strict gap\(\delta>0\)certificate valuestrict uniqueness
Numeric tolerance\(\varepsilon_{\rm num}>0\)certificate valueaudit
Route tagone of {FINITE_RADIUS, QUOTIENT_CLASS, INEQUALITY_SYSTEM, OTHER}choose routeaudit
Route payload locationfile / appendix namefinite data used to close the universal quantifieraudit
SCG regime + obstruction testP/A + pass/failrun 09C sanity checkaudit
SCG statement\(\lambda(w)\ge \lambda(w_*)+\delta\) for all other primitive periodic \(w\not\sim w_*\)verified from payloadstrict uniqueness

A practical guide to producing such a certificate is in 09B_SCG_CERTIFICATE_GUIDE.md.


9.4 Consequences to record (automatic once inputs are present)

If both (PA) and SCG are certified, then Paper 1 supplies:

  • (PO) periodic realization at \(\mathcal O_*\)
  • positive return density to \([\mathcal U_*]\) for every ergodic minimizing measure \(\mu\), hence exponential projective synchronization along minimizing dynamics

In the purely periodic case (\(\mathcal M_* = \{\mu_{w_*}\}\)), Paper 1 also gives explicit periodic return constants:

  • \(\eta_* = 1/|u_*| = 1/(|w_*|k_0)\)
  • return times to \([\mathcal U_*]\) form an arithmetic progression with step \(|u_*|\) (up to phase)

9.5 Projective regularity certificate (PR) on the minimizing support (Regime A route)

Use this section when the SCG obstruction triggers (Regime A) and a global cycle-gap statement is not being claimed.

A PR certificate replaces the SCG→PO→return-density route by an explicit return certificate on a specified minimizing subshift.

Record the following fields:

ItemSymbol / ValueHow to obtain (finite / checkable)Used by Paper 1
Regime tagA or Prun 09C obstruction testaudit
Minimizing support subgraphG_min ⊂ G (payload location)explicit vertex/edge lists or attached filedefines support Y
Selection route tagEDGE_PRUNING_LBper 10Baudit
Selection parametersδprune, εnum, L_max (if used)record from pruning payloadaudit
Selection payload logpath / hashattach payload list for deleted edgesaudit
Doeblin return wordu_*same as Section 9.1contraction block
Return check route tagAUTONOMOUS_RETURN_AUTOMATONper 10Aaudit
Return check resultpass/failcycle test on the avoidance automaton graph Hvalidity
Bounded-gap constantW_*safe bound W_* =V_min·u_*+u_*or exact longest-path boundreturn density
Uniform return density lower boundη* := 1/W*derivedcontraction rate

Once PR is present \(Doeblin block + τ* from Section 9.1, plus W* here\), Paper 1 can be invoked on the minimizing support without SCG (see Section 10).

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