B — Domain / Specialty Axis Filter Evidence

Capability: filter IUs by domain/specialty tag; show count, sample ids, and normalized↔denormalized consistency. Verdict: PASS. Channel: read-only via shipped DOT wrapper. Mutation: none.

B.1 Command & function

• DOT command: dot_iu_filter_axis_b (category=read, mutating=false, reversible=true).
• Function: public.fn_iu_filter_axis_b(p_tag_key text DEFAULT NULL, p_sample_limit integer DEFAULT 10) RETURNS jsonb — STABLE.

B.2 Input

SELECT fn_iu_filter_axis_b('legal_domain:knowledge_systems', 5);

B.3 Output (raw jsonb)

{
  "axis": "axis_b_domain_professional",
  "mode": "domain_filter",
  "tag_key": "legal_domain:knowledge_systems",
  "iu_count": 16,
  "tag_kind": "legal_domain",
  "sample_refs": [
    "knowledge/dev/laws/dieu39-knowledge-graph-law.md#0-tam-nhin",
    "knowledge/dev/laws/dieu39-knowledge-graph-law.md#10-roadmap",
    "knowledge/dev/laws/dieu39-knowledge-graph-law.md#1-26-bai-toan",
    "knowledge/dev/laws/dieu39-knowledge-graph-law.md#12-quan-he",
    "knowledge/dev/laws/dieu39-knowledge-graph-law.md#13-no-ky-thuat"
  ],
  "axis_b_consistency": { "consistent": true, "normalized_iu": 16, "denormalized_consistent": 16 },
  "source_document_distribution": [
    { "iu_count": 16, "legal_document": "doc:DIEU-39" },
    { "iu_count": 16, "legal_document": "doc:knowledge/dev/laws/dieu39-knowledge-graph-law.md" }
  ]
}

B.4 Interpretation / what a human can look at

• Count: 16 IUs carry the domain tag legal_domain:knowledge_systems (tag_kind legal_domain).
• Sample ids: five canonical addresses, all from the Điều 39 knowledge-graph law.
• Consistency: axis_b_consistency.consistent = true — the normalized count (membership rows in iu_metadata_tag, 16) equals the denormalized count (per-IU envelope iu_three_axis_envelope.axis_b_tags, 16). The two representations of the domain axis agree exactly.
• No-hardcode guarantee: the function resolves p_tag_key against iu_metadata_tag_registry (36 vocabulary rows); an unknown key returns an explicit refusal rather than a misleading empty success.

B.5 Other available domain tags (cardinalities, from registry/membership)

legal_domain:knowledge_systems=16, legal_domain:governance=5, legal_domain:technology=4; topic:knowledge_graph=10, topic:architecture=5; sectype:technical_spec=25; kind:law_unit=187.

B.6 Safety

Read-only STABLE function. No mutation, no gate touched.