Lean 4 cubical-transport HoTT engine + Rust naga-IR FFI. The backend that powers topolei. Cells-spec implementation; the proof IS the implementation.
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Maximus Gorog 60f7ecdf54
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@[metaPath] + structured failure + engine-bound methodologies
Phase D'.5 of ALGEBRA_PLAN.md and the §4.4 "Failure as a feature"
diagnostic.  Closes the methodology-transport loop end-to-end.

CubicalTransport/Algebra/MetaPath.lean (NEW):
- MetaPathEntry: source classifier + target classifier + witness Name.
- metaPathRegistryExt: persistent EnvExtension storing declared paths.
- @[metaPath SourceClassifier TargetClassifier] attribute: tags a
  declaration as a structural Path; the tagged decl serves as the
  witness theorem.
- Lookup helpers: findPathsFromSource / findPathsToTarget.
- Diagnostic printer.

CubicalTransport/Algebra/Methodology.lean:
- deriveByTransport replaces its earlier stub.  Walks the metaPath
  registry; for each path A ↦ B and each methodology M registered
  against A, derives a candidate against B (priority M.priority - 10)
  plus a candidate using the path witness directly (priority - 20).
- cubical_search now collects per-candidate failure reasons and
  emits a structured §4.4-shaped report:
    "candidates considered (N direct + K paths):
       ✗ candidate1 — error1
       ✗ candidate2 — applied but left subgoals
     would you like to register a new @[methodology] declaration?"
- Stage 1 (direct) and Stage 2 (transport) are exhausted in order;
  on full miss, structured report fires.

CubicalTransport/Algebra/Test.lean:
- Phase D'.5 example: refl_path_to_true tagged @[metaPath
  IsReflGoal IsTrueGoal] declares a structural Path.
- Engine-bound methodologies: compq_top_concrete (full-face CompQ),
  transpq_top_concrete (full-face TranspQ), transpq_interval_concrete
  (interval-line TranspQ).  All discharge their classifier via rfl
  (struct-projection-driven evaluation; no decide-on-free-vars
  failure).
- Two end-to-end cubical_search examples exercise the dispatch on
  concrete CompQ and TranspQ goals, succeeding via the engine-bound
  methodologies.

CubicalTransport.lean: import the new MetaPath module.

93/93 tests pass.  cubical_search now demonstrably closes both
trivial (True, Eq.refl, Iff.refl) and substantive (concrete
question-form equations) goals end-to-end.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-01 01:03:29 -06:00
.forgejo/workflows Add proprietary LICENSE; move CI to .forgejo/workflows/, run cubical-test 2026-04-27 23:04:16 -06:00
CubicalTransport @[metaPath] + structured failure + engine-bound methodologies 2026-05-01 01:03:29 -06:00
docs ALGEBRA Phases A+B+C+D' + cubical_search tactic + doc state-of-play 2026-05-01 00:59:06 -06:00
native/cubical REL2 Phase 1: CType.interval primitive 2026-04-30 18:47:13 -06:00
.gitignore Initial commit: topolei — cubical-transport HoTT in Lean 4 + Rust FFI 2026-04-27 20:40:45 -06:00
build.sh Split: engine = cubical-transport HoTT only 2026-04-27 21:35:01 -06:00
CubicalBench.lean Split: engine = cubical-transport HoTT only 2026-04-27 21:35:01 -06:00
CubicalTest.lean Split: engine = cubical-transport HoTT only 2026-04-27 21:35:01 -06:00
CubicalTransport.lean @[metaPath] + structured failure + engine-bound methodologies 2026-05-01 01:03:29 -06:00
lake-manifest.json Regenerate lake-manifest.json: package name cubicalTransport (was stale 'topolei') 2026-04-27 23:00:01 -06:00
lakefile.toml Split: engine = cubical-transport HoTT only 2026-04-27 21:35:01 -06:00
lean-toolchain Initial commit: topolei — cubical-transport HoTT in Lean 4 + Rust FFI 2026-04-27 20:40:45 -06:00
LICENSE Add proprietary LICENSE; move CI to .forgejo/workflows/, run cubical-test 2026-04-27 23:04:16 -06:00
NOTICE Add NOTICE: AI tooling acknowledgement; proprietary rights stand on human-directed whole 2026-04-27 23:10:32 -06:00
README.md Add proprietary LICENSE; move CI to .forgejo/workflows/, run cubical-test 2026-04-27 23:04:16 -06:00

cubical-transport-hott-lean4

A Lean 4 implementation of cubical-transport homotopy type theory (CCHM-flavor), with a fast Rust kernel exposed through C ABI.

The Lean side defines the syntax, semantics, and soundness theorems. The Rust side discharges the per-step β-rules of the evaluator. Lean axioms are routed through @[implemented_by] to Rust functions that return Lean objects in the same shape Lean would have produced; the soundness layer (CubicalTransport/Soundness.lean) certifies the backend at the boundary, so the kernel speed of the Rust code preserves the Lean-level proofs.

What's here

  • CubicalTransport/ — 22 Lean modules for syntax, substitution, dimensional structure, faces, typing, evaluation (eval / value / readback), transport, Glue, composition, and the soundness theorems.
  • native/cubical/ — Rust kernel (#![no_std], dual-target native staticlib + cdylib, wasm32 cdylib).
  • CubicalTest.lean, CubicalBench.lean — engine smoke + property tests (62/62 passing) and microbenchmarks.

Consuming the engine (with permission)

This Software is proprietary. See LICENSE — no use is granted by virtue of the repository being public. The instructions below are for the copyright holder and any party with prior written consent from mgorog@gmail.com.

Add as a Lake dependency from another Lean 4 project:

[[require]]
name = "cubicalTransport"
path = "../cubical-transport-hott-lean4"   # or git = "..."

Then import CubicalTransport.Syntax, import CubicalTransport.Eval, etc. Link against native/cubical/target/release/libtopolei_cubical.a in your own moreLinkArgs so the FFI symbols resolve.

Build

(cd native/cubical && cargo build --release)
lake build
./.lake/build/bin/cubical-test    # 62/62 tests pass

Reference

  • docs/FFI_DESIGN.md — C ABI contract between Lean and the Rust kernel.
  • docs/FFI_COMPLETENESS.md — per-function axiom audit.
  • docs/KERNEL_BOUNDARY.md — what this delivers in unmodified Lean 4 vs. what would need upstream Lean kernel work.
  • docs/NUMERICAL.md — numerical implementation principles.
  • docs/PHASE1_HISTORY.md — original transport/composition formalisation plan (archived; Phase 1 closed; preserved as methodology template for future phases).
  • docs/ZIGZAG_PORT.md — step-by-step Lean port plan for the n-category combinatorial engine (Phase 2+ higher-cell backend). Lands here in the engine. Read the cascade caveat at the top before editing: changes in the ported zigzag layer cascade to the sibling topolei repo.
  • native/cubical/README.md — Rust crate build + dev guide.
  • native/cubical/WASM.md — wasm32 ABI integration contract.

Used by

  • max/topolei — the cells-spec workspace interface, built on this engine. See its docs/cells-spec.md and docs/STATUS.md for the application-side picture.