#import "../generation_evidence.typ": load-generation-evidence
#let generation = load-generation-evidence()

#import "../draft_markers.typ": development_only, scientific_core_todo, prune_todo, review_note, review_strike

= Discussion <sec:thesis-discussion>

#prune_todo(
  [Complete this interpretation when the confirmatory comparisons are available.
  The present discussion interprets bounded renderer, runtime, collection and
  one-step results; the retained development hypotheses are not results.],
  source: [@sec:thesis-results and the frozen analysis plan],
  gate: [Each interpretation identifies a reported observation, a justified
  scope, and any competing explanation; no missing outcome is treated as zero.],
)

== What the available evidence establishes

*Measurement is conditional on the acquisition protocol.* The completed
renderer contrast supports candidate cropping only where full-scene selected
observations, successor histories and endpoint scoring remain equivalent.
Its earlier failure shows why faster rendering alone cannot qualify that
change. The separate runtime diagnostic found too little preparation work to
justify a larger mesh cache. Because the clocks cover different devices and
nested operations, it identifies further measurements rather than a universal
bottleneck or throughput guarantee.

*Generation yield and independent experience differ.* The historical
collection demonstrates retained continuations under its original evaluator.
The newer collections add targets and states within the same development
scenes. Neither a longer suffix nor another target draw adds an independent
scene, creates dense future labels, or admits a new observation protocol.
Successful input joins are necessary for fitting the declared objective, but
cannot establish predictive usefulness. Summed costs from collections with
different recipes also cannot replace the matched renderer comparison.

The post-hoc census makes this distinction concrete: its incremental TRAIN
chains broaden target and state exposure on already represented scenes.
@tab:generation-posthoc-coverage retains the independent-scene denominator.
Candidate support varies by family, and supported choices and finite immediate-gain
variation contract at later recorded acquisitions. These are measured properties
of the incumbent recipe. Scene geometry, target exposure, unequal quotas and
conditional continuation coverage can all contribute; none is isolated as a
causal explanation. Repeating supported choices within familiar scenes may
help fitting, but unseen-scene usefulness remains a separate evaluation.

*Ranking signal need not improve the selected action enough.* The frozen
one-step screen missed its practical-effect threshold, while exploratory
analysis found a ranking signal. Ranking many pairs correctly can coexist with
an error at the maximum that determines the chosen view. The constant
reference's tie rule further affects that choice. Post-hoc tie analysis helps
design another screen; it does not overturn the frozen negative result. Neither
absent useful signal nor representation loss has been established as its cause.

The larger fixed-seed analysis further separates action choice from numerical prediction error.
The final checkpoint has less regret than uniform choice on the exposed scenes,
while its mean absolute error exceeds that of the constant predictor. Its
regret advantage over the selected checkpoint remains uncertain. A model can
preserve a useful ordering while assigning inaccurate gain magnitudes, so neither
prediction error nor action regret substitutes for the other. These conditional
observations do not identify state aliasing, an architecture limitation or poor
collection as the cause, and leave the frozen checkpoint selector unchanged.

*Support and completion condition the conclusions.* The earlier proposal audit
remains a negative result for its own profile, even though later collection
succeeded. Radius limiting retained inspected family support without proving
wearer-motion realism or policy utility. Likewise, the B0/S endpoint contrast
is conditional on shared-complete chains; its small population and undefined
admission preservation leave the challenger unqualified. Retaining the baseline
is therefore a bounded development decision, not proof of optimality.

The interrupted continuing-value fit supplies a numerical failure, rather than
a comparison of successful multi-step estimators. A rising loss against a
changing bootstrap target can reflect target movement as well as prediction
error; it is not an independent measure of policy value. Repeating a qualified
fit with fixed-label checks and independent continuation outcomes is needed
before interpreting the learning method, representation or collector as its cause.

The principal held-out multi-step prediction and learned-policy endpoint
results remain unavailable. An implemented observed-target route does not
supply an evaluated actor-visible population.

== What the unresolved comparisons must distinguish

Measured reconstruction and actor information can evolve differently. After
an acquisition, the oracle evaluation cloud includes the selected surface, while
an actor restricted to compact root features and pose history may receive no
corresponding geometric evidence. Two histories that acquired different
surfaces can then appear identical to the scorer. This is a possible source of
state aliasing, not an observed explanation of a learned-policy result that has
yet to be measured.

An oracle may also choose a continuation using information unavailable to the
actor, so a gap to its choice need not be approximation error alone. On a fully
labelled successor shell, comparing an actor-selected continuation with the
oracle maximum isolates the consequence of the two selection rules under that
actor. It does not identify either the best possible actor or an irreducible
information gap. This distinction limits what a future finite-horizon result
can establish without prescribing a larger architecture in advance. A policy
may choose useful actions despite biased value estimates, so endpoint success
requires a separate prediction and calibration analysis before it supports
a claim about value accuracy.

== Data collection before action-space replacement

#review_note(kind: "scope", id: "X04", position: right,
  note: [Keep collection conditional on measured continuation coverage. Distinguish a matched collector robustness test from claims of reduced value bias or policy improvement.],
)[Additional interaction is relevant when the available proposals are useful but
their consequences are poorly represented in replay.] DAgger motivates collecting
supervision at learner-visited states @DAgger-ross2011, and Ball et al.
demonstrate retaining offline data during online off-policy learning
@RLPD-ball2023. Oracle-labelled transition aggregation would use that
distributional motivation, not implement the same imitation-learning algorithm
or inherit its guarantees. The proposed comparison therefore includes an
equal-cost exploratory-collection control on training scenes.

// evidence:
// - @DAgger-ross2011 -> https://proceedings.mlr.press/v15/ross11a/ross11a.pdf, Sec. 3, Algorithm 3.1 (learner-mixture rollouts and aggregation).
// - @RLPD-ball2023 -> https://proceedings.mlr.press/v202/ball23a/ball23a.pdf, Sec. 4, especially 4.1 (offline and online experience within off-policy learning).

The TRAIN-only analysis froze two collector nominations before validation was
exposed. The first is a matched quota test, retaining all four families and the
same proposal budget. Its frozen prescription is:
#quote(generation.nominations.at(0).proposed_change.replace("G60 quotas", "proposal counts"))
The second is a separate matched bearing-radius test:
#quote(generation.nominations.at(1).proposed_change
  .replace("radius", "radius ")
  .replace("incumbent", "incumbent ")
  .replace("unchanged", "unchanged ")
  .replace("m with", " m with")
  .replace("m step", " m step")
  .replace("m height", " m height")
  .replace("→", " → "))
Both nominations subsequently received the bounded three-scene Mac pilot in
@ssec:r1-collector-pilot. More labels were retained, but heterogeneous endpoints
and the absence of a learning comparison leave a collector winner unestablished.
Further independent scene/seed tests remain prospective. Preserve root, target
and assignment matching, complete attempted cost and independent endpoints;
testing quota and radius separately distinguishes allocation from geometry.
The validation readback selected neither intervention.

The matched Mac learning comparison in @ssec:mac-q1-comparison likewise shows
why more trajectories on the same scenes cannot be equated with more independent
experience. Its negative retention result and localized initial-state error
motivate fixed-checkpoint calibration and feature-use controls before another
architecture or optimizer claim. No active auxiliary-loss competition was needed
for drift to occur in that comparison.

#review_note(kind: "scope", id: "URS01", position: right,
  note: [Choose a recording-length or augmentation comparison only after aligning factual risk sets, acquisition costs and independently measured outcomes. Neither late support contraction nor record thinning establishes a learning benefit.],
  source: [@ssec:generation-supervision; source-bound research consolidation, 15 October 2026.],
  gate: [Freeze recording length separately from requested horizon, retain missing continuations, and qualify altered-history targets before a new fit.],
)[Late support contraction does not identify an optimal recording length.]
Selecting fewer training records can preserve the actual observations that
produced each retained state. Skipping acquisitions changes those observations
and may change subsequent actions. Such an altered history requires rebuilding
the observed or fused state and recomputing affected rewards, targets, validity
and returns. Joining factual transitions must retain elapsed-acquisition and
horizon semantics together with intervening returns. The learning benefits of
record subsampling and altered acquisition histories remain separate hypotheses.

Changing the action space addresses a different limitation. GenNBV's continuous
camera action and sequential coverage objective provide a precedent
@GenNBV-chen2024, not evidence that continuous control will improve this
thesis's target-specific metric. Such a comparison needs its own feasibility,
observation, simulator, and cost assumptions. New experience, updated model
weights, causal scene updating, and continuous actions are distinct
interventions. The optional fusion comparison associated with @ssec:rq2 keeps model weights fixed.

Changing the simulator or observation model would test a broader claim than
generalization to new ASE scenes. It can change candidate feasibility,
calibration, depth noise and reconstruction behaviour together. Those changes
need separate specification and comparison before transferring conclusions
about policy utility or numerical value accuracy.

// evidence:
// - @GenNBV-chen2024 -> docs/literature/tex-src/arXiv-GenNBV/3-Method.tex:13-25,76-95 (camera action, sequential observations and coverage reward).

The next evidential step is therefore narrower than an architecture change:
qualify the intended learning objective on the retained labels, evaluate
predictions against independent references, and complete matched policy
comparisons. The renderer endpoint validation already
closes its bounded acquisition contrast; the collection audits verify stored
endpoint bindings rather than independently recomputing their endpoint statistics. A supported negative result can answer
the bounded planning question. Missing support, unreliable measurement, and
unfinished runs cannot.
