docs: treat exact constant calibration as oracle

1 files changed, 10 insertions, 5 deletions

diff --git a/RAIN_EP_DILLAVOU_MATRIX.md b/RAIN_EP_DILLAVOU_MATRIX.md
index 094d9d6..3fe39e2 100644
--- a/RAIN_EP_DILLAVOU_MATRIX.md
+++ b/RAIN_EP_DILLAVOU_MATRIX.md
@@ -2,8 +2,11 @@
 
 ## Question
 
-Can a local neutral predictor remove a fixed hardware update offset without
-using a larger EP nudging voltage?
+The fixed-offset experiment is only an implementation sanity check. With an
+exact neutral observation, subtracting a strictly constant offset is already
+an oracle and cannot demonstrate an SDIL advantage. The scientific question
+is whether SDIL improves downstream accuracy when local hardware bias changes
+with device state and a stored constant is therefore insufficient.
 
 The primary corruption is the model in Dillavou et al., Eq. (7).  Every local
 parameter update receives a fixed, unknown, parameter-specific offset after
@@ -20,9 +23,11 @@ state-drift ratio is zero in all exact-model experiments.
 
 The correction is local and uses no backpropagation.  With the teaching input
 disabled, the update circuit exposes `B_i`.  The predictor stores this neutral
-measurement and subtracts it from subsequent updates.  Under the strictly
-constant model, constant calibration and SDIL innovation are expected to
-coincide.  A difference between them is neither predicted nor claimed.
+measurement and subtracts it from subsequent updates. Under the strictly
+constant model, constant calibration, SDIL innovation, and oracle subtraction
+are equivalent after the exact neutral observation. A difference between them
+is neither predicted nor claimed, and recovery in this setting is not evidence
+for SDIL.
 
 ## Frozen author protocol