Context
The proved finite-derivative algorithm and the stricter presentation discipline are different questions. This record names the intended restriction, but does not yet define a mathematical class of compilers over which existence or impossibility can be quantified.
Hypotheses and scope
- The output syntax uses the ordinary empty, epsilon, letter, union, concatenation, and star constructors.
- Residual enumeration, relation saturation, and an explicit least-fixed-point operator are excluded from the compiler interface.
Proof or evidence
The record pins a deliberately strict editorial discipline. It does not claim that every reasonable meaning of ‘purely inductive’ must satisfy these restrictions.
Verification notes
Review found that exclusions such as ‘do not enumerate a carrier’ can be disguised extensionally unless the allowed recursion schemes, auxiliary data, and cost model are formalized. The record is therefore not treated as a completed definition.
Limitations
- The definition may be narrower than other legitimate syntax-directed algorithms.
- No grammar of admissible compiler clauses, auxiliary operations, or extensional equivalence has been fixed.
- It does not itself establish existence or impossibility.