4189 — The Frozen Deletion Weights Are Not a Positive Instrument
Positivity test
On the eight Boolean deletion outcomes the frozen coefficients are
Four outcomes have negative coefficient. Therefore the augmentation cannot itself be interpreted as an ordinary positive measurement or classical mixture over deletion histories. In particular, conditioning on a deletion label is not automatically a physical which-route measurement.
The obstruction is basis-independent at the level of the declared Boolean outcomes: a positive instrument applied to arbitrary nonnegative sector readouts cannot reproduce negative coordinate functionals.
Thus
This strengthens Entry 2201: the cancellation is built into a signed interference functional. A physical preaggregation realization requires a quasiprobability, an ancilla with a signed observable, or some independently derived coherent equivalent.
Evidence
- Entries 2193 and 2199–2201
research/benincasa/checkers/deletion_positive_instrument_obstruction.rs