# PAT-0280 — Density Vacuum

## Ontology Metadata

Code: PAT-0280
Version: PAT-0280@0.1.0
Ontology release: 0.1.0
Updated: 2026-05-10T00:00:00Z
Canonical URL: /workbench/patterns/density-vacuum/

## Summary

A structural condition where a region expected to contain sufficient nodes, edges, coverage, or relationships falls below declared density thresholds.

## Primary Lenses

- LEN-0100 — Absence Lens
  - URL: /workbench/lenses/absence-lens/
  - Summary: Detects structurally required elements that are missing from the observed structure.
- LEN-0140 — Compression Lens
  - URL: /workbench/lenses/compression-lens/
  - Summary: Reduces structural graphs into stable minimal representations for comparison, redundancy detection, and diffing.

## Secondary Lenses

- LEN-0160 — Constraint Sufficiency Lens
  - URL: /workbench/lenses/constraint-sufficiency-lens/
  - Summary: Evaluates whether declared constraints are sufficient to eliminate structural degrees of freedom.

## Primary Issue Matches

- ISS-0077 — Diagnostic Area Has No Coverage
  - URL: /workbench/issues/diagnostic-area-has-no-coverage/
  - Summary: A known diagnostic area, failure mode, requirement, or review dimension has no Issue, check, rubric item, or workflow coverage.
- ISS-0081 — Evaluation Rubric Has Coverage Gap
  - URL: /workbench/issues/evaluation-rubric-has-coverage-gap/
  - Summary: An evaluation rubric, grading standard, or review checklist leaves part of the required evaluation space uncovered.
- ISS-0079 — Policy Area Has No Examples
  - URL: /workbench/issues/policy-area-has-no-examples/
  - Summary: A policy, rule, standard, or guidance area has no examples showing how it should apply to real cases.
- ISS-0078 — Workflow Stage Has Too Few Checks
  - URL: /workbench/issues/workflow-stage-has-too-few-checks/
  - Summary: A workflow stage lacks enough checks, gates, criteria, or review conditions to safely support the work it controls.

## Supporting Issue Matches

- ISS-0002 — Answer Has No Traceable Source Link
  - URL: /workbench/issues/answer-has-no-traceable-source-link/
  - Summary: The answer makes a claim, recommendation, citation, or factual statement without a source link or trace path that allows the user to verify where it came from.
- ISS-0022 — Missing Required Fields
  - URL: /workbench/issues/missing-required-fields/
  - Summary: The AI returns structured output that omits fields required by the schema, workflow, parser, form, or downstream consumer.
- ISS-0075 — Review Rubric Missing Required Criteria
  - URL: /workbench/issues/review-rubric-missing-required-criteria/
  - Summary: A review rubric, grading rule, evaluation checklist, or classification standard lacks criteria required to make the review reliable.