Status: Draft v0.2 — first thin-RFC pass. (v0.1 preserved at MPA-RFC-S_Scale-Management_Block-In.md as honest-scope reference; not authoritative.)
Targets: mpav1 (compressed, operational). Compression Axiom + operator algebra are the load-bearing imports.
Companion: Architectural Block-In v0.2, RFC-1 v0.2, RFC-2 v0.1, RFC-RI v0.1
This RFC inherits five principles from the Architectural Block-In, declared (not re-derived):
- Color-management discipline. Three layers (substrate-native / canonical / realizer-output); transforms declared, named, versioned, swappable.
-
Observer-driven scale management.
$\tau_{obs}$ is the camera; canonical representation is observer-relative. - Demand-bounded sufficiency. Canonical representation sized to declared demand. The MPA is not the bottleneck.
- Singular working-space path. Within an RFC version, exactly one shape. Plurality lives in drivers, intent flags, and version succession.
- Thin-RFC discipline. It was never brittle if it never broke.
RFC-S adds one principle, internal to scale management:
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RG flow as foundational structure. Scale-management semantics derive from the renormalization-group flow defined by mpav1's Compression Axiom (Wilson–Kadanoff + Banach contraction at
$\epsilon < 1$ ). The canonical representation, substrate gamut, intent operations, and behavior at boundary points are positions in or trajectories under this flow, not finite-engineering analogs reconstructed from color management. Color management is a finite discipline; MPA scale management is infinite. Infinity-machinery is imported directly, not patched on case-by-case.
The canonical representation at
| Object | Reading under RG flow |
|---|---|
| Vertex regime |
Fixed-point structure: |
| Edge |
Cooperativity class; preserved at fixed |
| Subgraph |
RG-invariant on substrates carrying it; topological. |
| Trail-class equivalence | Equivalence classes under the flow; cardinality |
Cross-position structure (auto-remap as
Pointer: mpav1 §Compression Axiom; §Three typed objects; §Boolean section.
A substrate's gamut is the image of its RG trajectory in canonical-representation space, parametrized by
| Axis | Substrate-declared content |
|---|---|
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| Persistence depth |
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| Reachable trail-class structure | Which fixed-point patterns the trajectory visits. |
A spec is in-gamut at operating
Pointer: mpav1 §Setting; §Capacity; §Falloff profile; Appendix G (Convergent Tower).
Five intents enumerate which canonical-representation invariants are preserved when a spec is out-of-gamut. The intent determines the mapping operation: scale uniformly along the gamut to fit, preserving the named invariant. (Rule, not per-intent operation table.)
| # | Name | Preserves | Sacrifices | Color analog |
|---|---|---|---|---|
| I1 | Regime-preserving | Vertex regime partition; edge-type partition; |
Absolute |
Perceptual |
| I2 | Drive-faithful | Exact |
Completeness (out-of-gamut rejected, diagnostic-listed) | Absolute colorimetric |
| I3 | Capacity-preserving |
|
Absolute drive level; non-sustained regime relationships | Saturation |
| I4 | Persistence-preserving |
|
Absolute drives; single-position regime relationships | (none — MPA-unique) |
| I5 | Signature-preserving | FDR-signature universality class (per regime / subgraph) | Exact signature parameters | Relative colorimetric |
Where intents are declared. At type-changing junctions (driver, auto-remap, realizer). Operator actions (
Composition. Two adjacent intents compose iff their preserved-invariant sets union without conflict. I2 (drive-faithful) does not compose with adjusting intents. Composition algebra beyond this rule is deferred (Appendix B).
Pointer: mpav1 §Operators; §FDR signatures (I5 universality classes); Appendix F (substrate-conditional reading).
The artifact a driver produces. Field enumeration here; machine-readable schema in Appendix A. Operating envelope is folded in as a driver-profile section, not its own RFC section.
| Section | Content |
|---|---|
header |
profile_version, target_rfc_versions, substrate_class, characterization_date, authority, validation_history |
operating_envelope |
initial_conditions, parameter_ranges, measurement_protocol — what calibration must verify |
gamut |
|
translation_field |
substrate-to-canonical and canonical-to-substrate maps, parametrized by |
intents |
per-intent: supported (bool); gamut-mapping operation; sacrifice declaration; use cases |
reference_outputs |
canonical test inputs with expected substrate responses + tolerance, for round-trip validation |
metadata |
methodology; known limitations; versioning history |
Characterization vs. calibration. Characterization produces the driver profile (one-time per substrate class). Calibration verifies the substrate is in the declared operating_envelope (per-experiment). A characterized-but-uncalibrated substrate has a profile that cannot be trusted on the current measurement; a calibrated-but-uncharacterized substrate has no profile at all.
Pointer: mpav1 §Substrate-conditional reading rules; Architectural Block-In §"What this means for drivers."
A driver is accepted iff forward and round-trip errors fall below intent-specific thresholds on every reference dataset the driver claims to support.
Protocol:
- Reference. Canonical reference dataset for the substrate class. (Surface-code QEC and habit-extinction are the proposed first two; see Architectural Block-In §"Reference substrates.")
- Forward. Driver under test produces canonical representation from reference substrate-native data.
- Forward comparison. Driver output vs. known-correct canonical representation, intent-specific metric.
- Backward. Reference realizer applied to driver's canonical output, producing predicted substrate-native data.
- Round-trip comparison. Predicted vs. original substrate-native data, intent-specific metric.
- Acceptance. Forward and round-trip errors both below thresholds, for every supported intent / dataset.
Per-intent metric (forward and round-trip share the metric):
| Intent | Metric |
|---|---|
| I1 regime-preserving | Hamming distance on regime partition; agreement on edge-type partition |
| I2 drive-faithful |
|
| I3 capacity-preserving |
|
| I4 persistence-preserving | Sequence distance on |
| I5 signature-preserving | Universality-class agreement; intra-class parameter distance |
Reference-substrate bootstrap. First reference per substrate domain is hand-built from mpav1 by-hand reading (mpav1 §5 + Appendix F for surface-code QEC). Subsequent drivers are validated against it. Multi-driver agreement supersedes single-reference validation once multiple drivers exist.
Pointer: mpav1 §5 (surface-code identification); Appendix F (substrate-conditional reading); RFC-2 v0.1 canonicalizes I5 metrics.
Boundary parameter values are points in the compactified parameter space, not separate edge cases per intent. Behavior is specified once per point; the intent's preserved invariant fixes its action at the point.
| Point | Physical reading | Default policy |
|---|---|---|
| Complexity Wall (mpav1 Appendix G). Tower fails to converge; further ascent thermodynamically forbidden. | Spec must declare wall-acceptance (terminal level) or fail. I4 extrapolates with growing |
|
| Boolean limit. Canonical representation collapses to |
Specs reduce to classical propositional logic; full operator algebra unnecessary. Recommend Boolean export. | |
| No drive. Only |
Reject specs with |
|
| Microscopic limit. Substrate-native granularity dominates; |
Below the driver's stated floor, the driver is invalid. | |
| Fully coarse-grained. All structure migrates to |
Spec's persistence profile must terminate; else flag as exceeding |
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| Regime-transition boundary. Reading ambiguous within transition zone of substrate-characterized width |
Zone reading undefined. I1 widens to next category; I2 reports ambiguous; substrate declares |
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| Theorem-9 boundary. Joint commitment infeasible. | RFC-1 mechanical check flags. Intent-determined: I2 hard-flags, I1 scales, I3 redistributes |
Pointer: mpav1 Theorem 9 (joint-commitment threshold); Appendix G (Convergent Tower / Complexity Wall); §Boolean section.
Driver-profile schema is the canonical exchange shape. Machine-readable schema at schema/driver-profile.v0.2.json. §4 mirrors the schema's field structure as a reading aid; v0.1's YAML sketch (v0.1 §6) remains a non-authoritative reference.
Items the next revision absorbs as needed:
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Auto-remap form: function vs. generator. v0.1 specifies auto-remap as a finite remap function. RG-thinking suggests the infinitesimal (tangent-flow) form: drivers specify the rule for small
$\tau_{obs}$ changes; finite remaps are integrated. Open whether all substrate classes admit clean infinitesimal rules and whether integration is tractable. v0.2 admits both forms; v0.3 may canonicalize. - Intent composition algebra past the union rule. §3 declares "union of preserved invariants without conflict." Whether this rule covers all admissible compositions is unverified at v0.2. If v0.3 needs a small composition table, that is the place a debt-marker would land — and the place sheaves (handoff Tier 3) might earn their weight.
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Lower-bound
$\varepsilon_n$ .$\varepsilon = 0$ is non-physical (information must be lost across real-scale coarse-graining). Substrate-specific$\varepsilon_n^{\min}$ declared in driver profile; form of declaration open. -
Observable sufficiency in round-trip validation. §5 assumes the backward map is invertible enough to validate; §4's
reference_outputsare the inputs that drive it. Neither states which observables jointly constrain which canonical-representation axes. Concrete force: an inversion against a single-mode gFDR locus constrains the vertex regime but is rank-deficient on the edge$\gamma$ — the round-trip would pass while leaving an axis untouched. v0.3 should add an observable-coverage obligation: a driver'sreference_outputsmust jointly constrain every canonical axis it claims to support. (Surfaced by the mpa-auditor mock-dataset slice; see that repo'sdocs/rfc-s-integration-notes.md.)
(Trail-class metric and per-regime universality invariants closed in mpav1 between v0.2 and the next RFC-S revision:
- Behavioral / evolving substrates. Substrates whose operating envelope evolves during measurement (training neural networks, evolving biological systems) do not admit a static driver profile. Out of scope. Future RFC-Beh or extension axis.
- Sheaf-theoretic pipeline composition. Tier-3 import (handoff §"Infinity-machinery available, ranked by fit"). Not earning weight at v0.2; reserve for v0.3 if §3's union rule proves insufficient.
- Coalgebraic trail-class equivalence. Reserve for when mpav1's open trail-class metric question becomes blocking.
- Reference-target standardization governance. Who declares which substrates are reference targets, on what criteria — operational, not protocol-layer.
| Version | Status | Change |
|---|---|---|
| v0.1 (Block-In) | preserved as honest-scope reference | Standards-body weight; ~5,800 words; 170–200-page projection. |
| v0.2 | current | Thin-pass rewrite. RG flow as foundational structure (§0 principle 6). Six body sections at half-page weight. Edge cases collapsed under compactification. |
Compatibility. Within v0.x: schema additions only. Removal of intents or change to compactification-point semantics requires v1.0+ revision. Drivers declare which RFC-S version they target.
Target: ≤5 pages including appendices (handoff §"What success looks like").
Body §0–§6 ≈ 3 pages; appendices A–C ≈ ½ page; versioning + self-check ≈ ¼ page. Total ≈ 4 pages. Pass.
For comparison: v0.1 ran ~620 lines of body and projected 170–200 pages at full ICC-v4-comparable resolution. The thin pass collapses 13 v0.1 sections to 6 active sections + 3 appendices. Compression mechanisms: RG flow + Banach contraction handle infinite coarse-graining as a single import (§0.6); compactification handles boundary behavior as points-in-space (§6); the five-intent table (§3) and round-trip protocol (§5) are preserved at full weight as the load-bearing exchange artifacts.
Debt-markers. None at v0.2. Pipeline composition — the handoff's flagged candidate to break the budget — was held to §3's intent-composition union rule plus deferral in Appendix C. If that rule proves insufficient against actual stress, v0.3 will carry a debt-marker naming the break and may import sheaves.