footprint concept
| Definition | The set of entries a reader reads. What the reader reads decides how warm and how stale the reader is. Chapter 13 section 13.3. |
|---|---|
| Example | A reader that touches 3 of a cache’s 10 entries has a footprint of 3, and only those 3 decide its hit rate. |
| Book | Data Mining as Observation, draft 0.2, commit f3914f0; entry id footprint, kind concept. |
| Status | no ledger row names this entry. Corrections: none recorded. |
| Defining equation | none |
| Assumptions and scope |
|
| Prior art | none recorded |
| Evidence | lean/DataMiningAsObservation/Cache.lean |
| Reviewed | not yet reviewed; generated 2026-09-10 from records at the commits on the provenance page. |
Equation
none
Conditions
- The set of entries a reader reads. The hit rate is one when the cache holds the footprint and does not move when entries outside it are added, so what the reader reads decides how warm, and how stale, the reader is.
- A replica is stale because of what the reader asks for. The hot reader read a false-clear rate of 0.99 and the cold reader 0.01 on the same store, and the aggregate described neither.
Conditions are curated in entries.toml rather than read
from a record.
Ledger
none
First stated
Chapter 13 section 13.3 of Data Mining as Observation, with
the reader’s footprint in
geometric-observation/chapters/ch19_the_certificate_that_ages.md:1-95.
Measurements
none
Failures and corrections
none
Invariance envelope
none declared
Machine checked
lean/DataMiningAsObservation/Cache.lean,
theorems hitRate_mem_unit, hitRate_cold,
hitRate_warm, hitRate_mono,
hitRate_footprint, at observation-data-mining f3914f0; what
the check covers is stated in the book’s appendix
C.
Used in
Data Mining as Observation chapters 0, 2, 11, 12, 13, 14.
Related
cache; cold, warm; replica; false-clear rate; read subspace.
See also
Book equations stated beside the entry’s terms, not defining it: 0.26, 13.2, 13.1.
Ledger rows that cite the entry’s records without naming it: OT-11, GO-12.
Sources-table rows that share a record with the entry without naming it: chapter 13 section 13.2, chapter 13 section 13.3.
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.