[generated] kernel theorem axeyum.string.2.length_eq_foldr (string prelude, axiom-free, prose not curated)

Identifier: F:string-length-eq-foldr
Proof route: kernel-lean
External status: Not recorded
Axiom footprint: Empty

Recorded description

MECHANICALLY GENERATED, UNREVIEWED PROSE -- this sentence deliberately makes NO mathematical characterisation of the theorem. What is asserted, and all that is asserted, is this: the kernel declaration `axeyum.string.2.length_eq_foldr` is a `Declaration::Theorem` admitted into the environment by `build_string_prelude` through the trusted `Kernel::add_declaration` gate, which re-derives its type from its proof term; its type is recorded verbatim in `formal.statement`; and its axiom footprint, as computed by `Kernel::axiom_footprint`, is empty. The authoritative content of this fact is `formal.statement`. A human-readable characterisation of what axeyum.string.2.length_eq_foldr SAYS has not been supplied, because a generator cannot supply one honestly -- see `notes`.

Formal statement

theorem axeyum.string.2.length_eq_foldr : ((x0 : axeyum.string._2.Str) -> Eq.{1} AxNat (axeyum.string._2.length x0) (axeyum.string._2.foldr.{1} AxNat (fun (x1 : axeyum.string._2.Char) => fun (x2 : AxNat) => AxNat.succ x2) AxNat.zero x0))

Dependencies

The graph shows direct ledger edges. Follow a node to open its artifact page.

0 direct dependencies 0 direct dependents

Evidence

kernel-axeyum.string.2.length_eq_foldr

Kind: kernel-term
Status: checked

Supports: axeyum.string.2.length_eq_foldr is admitted by the trusted kernel gate with the type recorded in formal.statement.

Checker command

cargo run -q --release -p axeyum-lean-kernel --example theorem_dependency_inventory -- axeyum.string.2.length_eq_foldr 2>/dev/null | grep -cE '^axeyum\.string\.2\.length_eq_foldr[[:space:]]'

Evidence notes

Two independent failure modes, so the exit status depends on the finding rather than on the run completing: theorem_dependency_inventory exits non-zero when a NAMED filter matches nothing, and grep -c exits 1 printing 0 when the anchored line is absent. Anchored with [[:space:]], never \t -- in a scripted (GNU) grep \t is a literal t. grep -c rather than grep -q, which would SIGPIPE the producer under pipefail. --release is MANDATORY: this tool builds creal/complex/cpoint, which overflow the default debug thread stack.

footprint-axeyum.string.2.length_eq_foldr

Kind: exhaustive-enumeration
Status: checked

Supports: axiom_footprint: [] -- the string prelude's trusted surface is empty, which bounds axeyum.string.2.length_eq_foldr.

Checker command

cargo run -q --release -p axeyum-lean-kernel --example nat_axiom_inventory -- --require-axiom-free string

Evidence notes

--require-axiom-free exits non-zero when the named prelude's trusted surface (Axiom + Opaque + Quotient) is not empty, and errors rather than silently passing for a prelude the run never built. A declaration cannot depend on a trusted declaration the environment does not contain, so an empty string surface bounds every declaration in it, including axeyum.string.2.length_eq_foldr. This is a whole-prelude bound, not a per-declaration measurement; the per-declaration figure is the footprint column of kernel_declaration_projection, measured 0 for this row.

Provenance

{
  "date": "2026-08-27",
  "curation": "generated-unreviewed",
  "generated_by": "scripts/gen-kernel-facts.py",
  "established_by": "axeyum-lean-kernel build_string_prelude (crates/axeyum-lean-kernel/src/string_prelude/)",
  "source": "Derived mechanically from the unfiltered emit of `cargo run -q --release -p axeyum-lean-kernel --example kernel_declaration_projection`, which prints one TSV row per declaration whose fields are (prelude, kind, display name, axiom-footprint size, direct type declarations, direct declarations, direct theorems, Kernel::render_lean(declaration.ty())). formal.statement is that last field verbatim; depends_on is the direct-theorem column intersected with this ledger's registered facts; axiom_footprint is the footprint-size column, cross-checked by the whole-prelude nat_axiom_inventory run recorded in the second evidence row. No field was hand-transcribed and no prose was authored."
}