Proof Path TheoryReading edition

Versioned proof objects

Reading tools
Reading libraryFind statementsInspect Lean
Switch work

Saved reading

Read side by side

Start reading

Resources & source

Read and explore

Proofs and implementation

About this work

Other resources

Original TeX with line links · Download TeX

The wording and mathematics follow the retained manuscript. This reading format does not add a proof review or extend Lean coverage.

Skip contents and start reading

18 Versioned proof objects

A proof archive changes. Claims are strengthened, corrected, refuted, or split. A reproducible theory therefore needs stable identifiers and explicit version relations.

Definition 18.1: Versioned proof object

A versioned proof object is a sequence

\[ {\mathcal P}_0\longrightarrow{\mathcal P}_1\longrightarrow\cdots \]

whose nodes and justifications carry stable identifiers. Each transition records additions, removals, altered scopes, evidence changes, and a digest of its parent version.

Definition 18.2: Append-only certified update

An update \({\mathcal P}_i\to{\mathcal P}_{i+1}\) is append-only certified when every existing node, admissible-leaf status, evidence record, interpretation, and certified justification remains unchanged. The later field may add records and certified rules but may not withdraw an earlier admitted leaf or change the scope of an earlier inference.

Theorem 18.3: Derivability is monotone under append-only updates

Every target derivable in \({\mathcal P}_i\) remains derivable in \({\mathcal P}_{i+1}\) under an append-only certified update.

Proof

A certificate in \({\mathcal P}_i\) uses only nodes and certified justifications that remain unchanged in \({\mathcal P}_{i+1}\). The same selected subfield therefore satisfies the same derivability closure in the later version.

Retractions and semantic changes are not append-only. They require invalidation analysis.

Definition 18.4: Syntactic affected set

For a changed node set \(X\subseteq V\), define

\[ \operatorname{Aff}(X)=X\cup{\operatorname{Desc}}(X), \]

where descendants are computed in the declared dependency graph.

Theorem 18.5: Minimal closed syntactic review set

The set \(\operatorname{Aff}(X)\) is the unique smallest node set \(Y\) such that \(X\subseteq Y\) and \(Y\) is closed under outgoing dependency edges: whenever \(u\in Y\) and \(u\to v\) is a declared dependency edge, then \(v\in Y\).

Proof

By construction, every node reachable from \(X\) lies in \(\operatorname{Aff}(X)\), so the set contains \(X\) and is closed under outgoing edges. Let \(Y\) be any other set with those two properties. Every directed path beginning in \(X\) remains inside \(Y\) by induction on path length. Hence every descendant of \(X\) lies in \(Y\), and \(\operatorname{Aff}(X)\subseteq Y\).

Changing L 1 marks L 1, L 2, and B for syntactic review. The lower branch has no forward dependency path from L 1. Membership in the review set is not a claim that a theorem has become false.
Figure 21. Changing \(L_1\) marks \(L_1\), \(L_2\), and \(B\) for syntactic review. The lower branch has no forward dependency path from \(L_1\). Membership in the review set is not a claim that a theorem has become false.

View full-size figure (new tab)

The theorem is intentionally syntactic. A descendant can survive after rechecking. The affected set says where review is required, not where falsehood is guaranteed.

Source and conversion record

Source SHA-256: ce05e88b439e9fd55ef6eb04da708a63ce02e6627424e6daac0dca4177b8ab51

Unsupported prose commands stop the build. The mathematical expression sequence is checked against the source, with manuscript macros expanded for display.

Conversion records

Notation in Proof Path Theory

Look up a symbol without leaving this chapter. Select text before opening help to search for it.

Search this work’s notation.

    Symbols can have different meanings in different passages. Read each result in its own context.

    Open the full notation index