README.md

metadata

license: cc-by-4.0
task_categories:
  - text-classification
  - token-classification
language:
  - uk
tags:
  - legal
  - legal-nlp
  - legislative-quality
  - definitional-defects
  - circulus-in-definiendo
  - ignotum-per-ignotum
  - ukrainian-law
size_categories:
  - 1K<n<10K

DefectRadar: Definitional Defects in Ukrainian Legislation

Corpus of 5,799 legal definitions extracted from 879 Ukrainian laws (out of 44,021 active legislative acts), annotated for two types of definitional defects:

• Circulus in definiendo (tautology): the definition uses the term being defined (or its morphological derivative) in the differentia specifica
• Ignotum per ignotum (unknown through unknown): the definition relies on terms that are not defined in the same law

Key Statistics

Metric	Value
Legislative acts scanned	44,021
Laws with definitions	879 (2.0%)
Unique definitions	5,799
Circulus in definiendo	1,880 (32.4%)
Cross-reference ignotum	1,885 (32.5%)
Both defects	749 (12.9%)
Any defect	3,016 (52.0%)

Error Analysis (LLM-as-Judge Validation)

Pipeline-flagged circulus cases were independently classified by a RAG-augmented GPT-4o judge:

Classification	%
Domain terminology reuse (morphologically circular but substantively meaningful)	84.8%
True defect (normatively empty)	9.1%
False positive	6.1%

Ignotum severity stratification:

Severity	%
Cross-reference gap (defined in another law)	70.8%
Critical (undefined anywhere in corpus)	20.8%
Common (well-known, no definition needed)	8.3%

Data Fields

Field	Type	Description
rada_id	string	Verkhovna Rada law identifier
law_title	string	Official title of the law
definiendum	string	The term being defined
genus_proximum	string	Superordinate category (genus)
differentia_specifica	string	Distinguishing characteristics
full_definiens	string	Complete right-hand side of the definition
is_circulus	bool	Pipeline circulus detection result
circulus_tier	string	Detection tier (morphological / semantic)
overlapping_lemmas	list[str]	Lemmas shared between definiendum and differentia
circulus_explanation	string	Pipeline explanation
has_ignotum	bool	Whether undefined terms were found
undefined_terms	list[str]	Terms used but not defined in this law
ignotum_severity	string	Severity classification
ignotum_explanation	string	Pipeline explanation

Source

Definitions extracted from the Verkhovna Rada Open Data portal (data.rada.gov.ua) using the LEX AI platform's RadaLegislationAdapter. Corpus snapshot: April 2026.

Pipeline

The DefectRadar pipeline operates in three stages:

1. Definition extraction: rule-based (em-dash copula patterns) + fine-tuned XLM-RoBERTa for inline definitions
2. Circulus detection: Ukrainian lemmatization (pymorphy2-uk) + genus exclusion + discriminating-adjective overlap
3. Ignotum detection: cross-legislative definition graph across 879 laws

Pipeline code: github.com/overthelex/secondlayer/tree/main/scripts/defectradar

Citation

@article{ovcharov2026defectradar,
  title={DefectRadar: Automated Detection of Definitional Defects in Legislation via Morpho-Semantic NLP Pipeline over 24,000 Ukrainian Laws},
  author={Ovcharov, Volodymyr and Kyrychenko, Ihor},
  journal={arXiv preprint},
  year={2026}
}

License

CC BY 4.0