Corrigenda Are Operations over Operations

A corrigendum (oikaisuilmoitus in Finnish) is a published correction to an enacted text. Systems may expose it as an annotation or apply it during consolidation, but either treatment can obscure which source changed the visible text.

For replay, model a corrigendum as a higher-order operation: it corrects a prior amendment operation rather than only patching the current statute text.

Corrigenda Change Provenance

Consider an amendment A that changes section 12 of a statute. A corrigendum C is published correcting the text of amendment A. The question is: what is the correct state of section 12?

A flat correction applied to the consolidated text may produce the current visible wording while losing:

• The provenance chain — which version of the amendment instruction produced the current text
• The temporal semantics — the corrigendum was published at time T₂, but may correct an amendment published at T₁. Whether the correction is retroactive, prospective, or merely evidential depends on the jurisdiction and correction type.
• The composition — if another amendment B was applied between T₁ and T₂, and B was based on reading the uncorrected text of A, the interaction is invisible in a flat model.

In a compiler model, a corrigendum is: C : A → A', where A is the original amendment and A' is the corrected amendment. The replay engine then applies A' instead of A, producing different state from the same source chain.

Bitemporal consequences

Corrigenda create bitemporal situations:

• Transaction time — when the corrigendum was published
• Valid time — the point in legal history the correction purports to address; whether it has retroactive effect depends on the jurisdiction and correction type

Before the corrigendum, the observable publication surface is the state produced by A. After the corrigendum, the system may need to expose both the original publication-time state and the corrected legal/evidential state. The legal consequence varies by source regime and correction type.

A consolidation view generally exposes the corrected surface. A replay compiler can retain both the pre-correction publication surface and the corrected state, with the choice tied to the query and the declared time model.

The Finnish corpus

Historical project analysis identified oikaisuilmoitukset published in Säädöskokoelma — official correction notices — affecting multiple statutes. This article uses that analysis as context; a current total would require a dated, citable corpus.

In the inspected Finnish source lane, correction notices are available as PDFs rather than as machine-readable operation records. A corrected text can appear in the consolidated view while the correction mapping remains implicit. In affected cases:

• the enacted XML can contain the uncorrected text;
• the consolidated view can show the corrected text; and
• the inspected archive may have no machine-readable artifact recording the mapping between them.

LawVM extracts corrigendum operations from Säädöskokoelma source and applies them as explicit patches to the amendment instruction chain. In the Finnish corpus, corrigendum handling creates a distinct class of replay-vs-comparison-surface divergences where the source correction layer must be reviewed explicitly rather than hidden as editorial cleanup.

The paradox

LawVM without corrigendum patches may match Finlex better on the similarity metric, while LawVM with corrigendum patches may better reflect a correction source. That can score worse against Finlex, because the benchmark measures Finlex agreement, not legal correctness.

This is a concrete example of why a single similarity score is misleading. The system that agrees more with the comparison surface is not automatically better supported by the correction source. The residual taxonomy exists to make this distinction visible.