4.3. Ambiguity and static certificates🔗

The grammar class permits ambiguous alternatives and token splits. The reference decoder enumerates full parses and chooses the first, so recognition alone does not imply that captures or values are grammar-determined.

Triptych.GrammarCaptureFunctional states the needed semantic property. A conservative Triptych.Grammar.staticUnique checker proves it for deterministic fragments such as Graph and Decimal. When certification succeeds, Triptych emits premise-free decode/render, view/render, value-coherence, and relational-parser theorems.

Structural derivation membership is still generated when the conservative checker cannot certify a grammar. In that case, exact first-decode roundtrip retains an explicit capture-functionality premise.