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read distortion concept

DefinitionThe error as a consumer experiences it, the trace of the read operator times the error's second-moment matrix, which is its covariance when the error is centered. For the identity reader it is mean squared error. Equation 0.10.
ExampleA reader with operator diag(1, 0) charges a code with errors (0.3, 1.7) only 0.3.
BookData Mining as Observation, draft 0.2, commit f3914f0; entry id read-distortion, kind concept.
Statusno ledger row names this entry. Corrections: none recorded.
Defining equationnone
Assumptions and scope
  • Exact, with no centering, for a fixed read operator, which is the affine case. For a nonlinear consumer whose error depends on the row it is a first-order factorized surrogate, exact when the local operator and the error’s outer product are uncorrelated across rows.
  • The second-moment matrix of the error, not its covariance, unless the error is centered by construction.
  • The trace of the second moment is the mean squared vector norm, which is the dimension times the per-coordinate mean squared error.
Prior artThe consumer-weighted squared error. Task-based quantization studies the same objective for a known task.
Evidencegeometric-observation/chapters/ch05_the_read_metric_and_the_quotient.md:49-75, lean/DataMiningAsObservation/ReadDistortion.lean
Reviewedsemantic review 2026-09-06; generated 2026-09-10 from records at the commits on the provenance page.
first codesecond codereaderfirst codesecond codesame trace
The error a code costs a reader, weighted by what it reads.

Equation

none

Conditions

Conditions are curated in entries.toml rather than read from a record.

Ledger

none

First stated

Volume 14, chapter 5, geometric-observation/chapters/ch05_the_read_metric_and_the_quotient.md:49-75, DOI 10.5281/zenodo.21776291, and chapter 2 of the same volume for the failure of observer-free measurement.

Measurements

Where the book states it Numbers, as the book’s sources table records them Source
chapter 2 section 2.2 read distortion controls but is not a complete rank statistic, twelve of twelve, one middle pair misordered, NEG-9 geometric-observation/chapters/ch05_the_read_metric_and_the_quotient.md:49-75

Failures and corrections

none

Invariance envelope

Survived.

Boundary measured.

Machine checked

lean/DataMiningAsObservation/ReadDistortion.lean, theorems read_distortion, identity_reader, quad_one, at observation-data-mining f3914f0; what the check covers is stated in the book’s appendix C.

Used in

Data Mining as Observation primer L, chapters 1, 2, 4.

Related

the flip; alignment; identity reader; quotient.

See also

Book equations stated beside the entry’s terms, not defining it: 0.10, 1.2, 4.1.

Ledger rows that cite the entry’s records without naming it: GO-2 (pos. half: consumer-projected covariance controls).

Sources-table rows that share a record with the entry without naming it: chapter 1 section 1.4, chapter 2 section 2.2, chapter 4 section 4.3.

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.

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