anti arm instrument
| Definition | In a flip comparison, a third code built to destroy the consumer's read subspace at the same bits. It is expected to score worst, and a comparison in which it does not is not a flip. Chapter 4. Also anti-arm. |
|---|---|
| Example | Put the whole error of 0.4 on the direction the reader reads and the reader sees 0.4; put it on the other direction and the reader sees zero. |
| Book | Data Mining as Observation, draft 0.2, commit f3914f0; entry id anti-arm, kind instrument. |
| Status | no ledger row names this entry. Corrections: none recorded. |
| Defining equation | Book equation 4.5. |
| Assumptions and scope |
|
| Prior art | none recorded |
| Evidence | lean/DataMiningAsObservation/AntiArm.lean |
| Reviewed | not yet reviewed; generated 2026-09-10 from records at the commits on the provenance page. |
Equation
Book equation 4.5.
\[\text{flip}:\quad \mathrm{task}(O)>\mathrm{task}(R)\ \ \text{and}\ \ \operatorname{tr}M^{O}_\delta>\operatorname{tr}M^{R}_\delta,\qquad \mathrm{task}(\text{anti})<\mathrm{task}(R),\qquad \text{bits}(O)=\text{bits}(R).\]
Conditions
- The anti arm is matched on bits with the other two codes, and its purpose is to show that the read subspace is what the comparison is about, since destroying it should be worst.
- A comparison in which the anti arm is not worst has not shown a flip, whatever the other two arms did.
Conditions are curated in entries.toml rather than read
from a record.
Ledger
none
First stated
Volume 14, chapter 8,
geometric-observation/chapters/ch08_value.md:1-30, DOI
10.5281/zenodo.21776291, as the third arm of every registered flip.
Measurements
none
Failures and corrections
none
Invariance envelope
none declared
Machine checked
lean/DataMiningAsObservation/AntiArm.lean,
theorems readDiag_le_max, readDiag_le_total,
anti_arm_worst, at observation-data-mining f3914f0; what
the check covers is stated in the book’s appendix
C.
Used in
Data Mining as Observation chapters 4, 6, 7, 12.
Related
the flip; read distortion; read operator.
See also
Ledger rows that cite the entry’s records without naming it: GO-2 (neg. half: not reconstruction), NEG-16 (KV serving, end-task), GO-B-whale (038), GO-B-blind (041).
Sources-table rows that share a record with the entry without naming it: chapter 1 section 1.4, chapter 2 section 2.5, chapter 4 section 4.3, chapter 4 section 4.4, chapter 6 section 6.2.
Status
Generated 2026-09-10 by encyclopedia/generate.py; book
at observation-data-mining f3914f0; the commit of every record is listed
in the encyclopedia’s provenance.