Complete the explosion module for layout computation:
- Poset methods: is_less_than, less_than_or_equal, is_comparable,
minimal_elements, maximal_elements, topological_sort
- Covering relations: compute_covers() from poset ordering
- k_points: Full implementation with proper covering relation computation
- Point ordering: Product ordering on height labels with zigzag structure
- HeightLabel ordering: r_j < s_j < r_{j+1} within each dimension
- Injectification stub for future layout integration
The poset structure captures the combinatorial data needed for
embedding Pt_n(X) -> R^n in the layout algorithm.
All 55 tests pass.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Initial structure implementing the zigzag construction for associative
n-categories (LICS 2022 paper). Includes:
- monotone.rs: MonotoneMap with Wraith's R equivalence (complete)
- zigzag.rs: Zigzag<T>, ZigzagMap<S> with composition
- diagram.rs: Diagram, DiagramN, Cospan, Rewrite, Cone types
- signature.rs: Generator, Signature (complete)
- degeneracy.rs: Degeneracy detection stubs
- normalise.rs: Construction 17 algorithm structure
- typecheck.rs: Type checking against signatures
- explosion.rs: k-points and Poset for layout
- layout.rs: SpringConstraint API surface
All 33 unit tests pass.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
