docs: integrate publication analysis — Alexa, Bobenko, Springborn, Crane, Lutz

Add phases 9d / 9e / 9f and literature citations derived from a systematic
review of the five authors' publication lists (Tier 1 / 2 / 3 analysis).

phases.md:
  - Phase 9d: ConesUtility port (9d.1) + non-Euclidean cone extensions
    (9d.2, RESEARCH) + StereographicUnwrapper (9d.3)
  - Phase 9e: CirclePatternLayout + CirclePatternUtility (Java port)
  - Phase 9f: Polygon Laplacian on non-triangular meshes (Alexa 2011/2020,
    RESEARCH — no Java equivalent)
  - Phase 9b-analytic: add Rivin-Springborn 1999 as Schläfli source
  - Phase 10b: add Bobenko-Bücking 2009 + Bobenko-Lutz 2024 IMRN
  - Phase 10c: add Lutz 2023 (canonical tessellations) + Bobenko-Lutz 2024
  - Phase 10c' KoebePolyhedron: add Bowers-Bowers-Lutz 2026 rigidity result

references.md:
  - Crane et al. 2018 Optimal Cone Singularities (Phase 9d.2)
  - Bobenko-Lutz 2025 Discrete & Comput. Geom. (Phase 9d.2)
  - Bobenko-Lutz 2024 IMRN (Phase 10b/c)
  - Lutz 2023 Geom. Dedicata (Phase 10c)
  - Lutz PhD thesis TU Berlin 2024 (Phases 9d.2, 10b, 10c)
  - Bowers-Bowers-Lutz 2026 (Phase 9b-analytic + 10c')
  - Alexa-Wardetzky 2011 + Alexa 2020 (Phase 9f)
  - Bobenko-Bücking 2009 (Phase 10b)
  - Rivin-Springborn 1999 (Phase 9b-analytic)

research-track.md:
  - New entry: Phase 9d.2 non-Euclidean cone extensions (Bobenko-Lutz 2025
    + Crane 2018), with acceptance criteria
  - New entry: Phase 9f polygon Laplacian (Alexa-Wardetzky 2011 / Alexa 2020),
    with acceptance criteria

java-parity.md:
  - Split cone-metrics row into Euclidean (9d.1 port) and non-Euclidean
    (9d.2 research) with literature references
  - Add ConesUtility to "utility classes not yet ported" table

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
Tarik Moussa
2026-05-25 23:51:26 +02:00
parent f25174ed69
commit 068df474b1
4 changed files with 167 additions and 1 deletions

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@@ -109,6 +109,8 @@ mesh type.
9b-analytic Full analytic HyperIdeal Hessian via Schläfli identity
→ planned, see research-track.md
Mathematical source: Springborn 2020 §4 + Schläfli 1858/60
+ Rivin, Springborn 1999 "The Schläfli formula in
Einstein manifolds with boundary" (ERA-AMS 5)
+ Cho-Kim 1999 + Glickenstein 2011 §4
Algorithm: explicit chain rule through (bᵢ,aₑ) → ℓᵢⱼ → ζ₁₃/ζ₁₄/ζ₁₅ → αᵢⱼ/βᵢ
Includes: short LaTeX correctness note in doc/math/.
@@ -127,6 +129,69 @@ mesh type.
+ holonomy infrastructure.
Effort: ~2 weeks for fundamental polygon, +2 weeks for surgery
layer, +1 week integration.
9d — Cone singularities + sphere atlas (Java port + research extension)
────────────────────────────────────────────────────────────────────────
9d.1 ConesUtility (Java port — Euclidean only)
→ cones_utility.hpp
Java source: ConesUtility.java (~200 lines)
Mathematical reference: Troyanov 1991 + Springborn 2020 §3
Port scope: prescribed cone angles Θᵥ ≠ 2π in Euclidean mode.
Status: 🔲 planned
9d.2 Non-Euclidean cone extensions (RESEARCH, not in Java)
→ extend ConesUtility to HyperIdeal + Spherical modes
Java source: NONE — Java ConesUtility is Euclidean-only.
Mathematical reference:
Bobenko, Lutz 2025 "Decorated Discrete Conformal Equivalence in
Non-Euclidean Geometries" (Discrete & Comput. Geom. 2025,
arXiv:2310.17529) §3 — decorated DCE framework unifying cone
singularities and cusps in hyperbolic + spherical geometry.
Crane, Soliman, Ben-Chen, Schröder 2018 "Optimal Cone Singularities
for Conformal Flattening" (ACM SIGGRAPH 2018) — L¹-optimal
automatic cone placement; directly applicable to 9d.2 algorithm.
Status: 🔲 planned
9d.3 StereographicUnwrapper (Java port)
→ stereo_unwrapper.hpp
Java source: StereographicUnwrapper.java (266 lines)
Converts spherical DCE output (Point_3 on S²) to a 2-D atlas
via stereographic projection + Möbius centring.
Closes the visualisation gap from discrete_conformal_map_spherical().
Effort: small (~3 days).
Status: 🔲 planned
9e — CirclePatternLayout (Java port)
─────────────────────────────────────
9e CirclePatternLayout + CirclePatternUtility (Java port)
→ circle_pattern_layout.hpp
Java sources: CirclePatternLayout.java + CirclePatternUtility.java
+ CPEuclideanRotation.java
Mathematical reference: Bobenko-Springborn 2004 variational principle
+ Bobenko-Hoffmann-Springborn 2006 "Minimal
surfaces from circle patterns" (Discrete &
Comput. Geom. 35, 2006).
Status: 🔲 planned
9f — Polygon Laplacian (RESEARCH — no Java equivalent)
──────────────────────────────────────────────────────
9f Discrete Laplacian on general polygonal meshes
→ polygon_laplacian.hpp
Java source: NONE
Mathematical reference:
Alexa, Wardetzky 2011 "Discrete Laplacians on General Polygonal
Meshes" (ACM SIGGRAPH 2011) — virtual-node construction,
polygon cotangent weights extending the Pinkall-Polthier formula.
Alexa 2020 "Discrete Laplacians on General Polygonal Meshes"
(ACM TOG 39, 2020) — extended journal treatment, error bounds.
Enables: DCE energy evaluation on quad-dominant / Voronoi /
polygon meshes without forced triangulation.
Replaces euclidean_hessian.hpp for non-triangular inputs.
Status: 🔲 planned (pure research, no Java source)
Effort: medium (~2 weeks core + tests; +1 week Newton integration).
```
9d — Cone metrics + sphere utilities (Java port — 2026 library scan)
@@ -295,6 +360,13 @@ Phase 10 Global uniformization for genus g ≥ 2
→ Ωᵢⱼ = ∫_{bⱼ} ωᵢ
→ Reduction to Siegel fundamental domain via Sp(2g,).
Mathematical reference: Bobenko-Springborn 2004 + Gottschling 1959.
Bobenko, Bücking 2009 "Conformal Structures and
Period Matrices of Polyhedral Surfaces" — discrete
period matrix Ωᵢⱼ on polyhedral surfaces.
Bobenko, Lutz 2024 IMRN "Decorated Discrete Conformal
Maps and Convex Polyhedral Cusps" — uniformization
theorem connecting cusps ↔ hyperideal vertices
(bridges Phase 2/3 HyperIdeal geometry to 10b).
Java partial reference: DiscreteRiemannUtility.java (186 lines).
Requires: 10a.
Effort: ~1 week net after 10a.
@@ -318,6 +390,14 @@ Phase 10 Global uniformization for genus g ≥ 2
→ Embedding as H²/Γ with Γ ⊂ PSL(2,) a Fuchsian group.
Mathematical reference: Sechelmann 2016 §6 (discrete instance);
Bers 1960 (continuous theory).
Lutz 2023 "Canonical Tessellations of Decorated
Hyperbolic Surfaces" (Geom. Dedicata 217,
arXiv:2206.13461) — canonical Delaunay tessellations
in Penner coordinates; unifies the decorated
framework with the fundamental domain construction.
Bobenko, Lutz 2024 IMRN (arXiv:2305.10988) —
discrete uniformization theorem for decorated
piecewise Euclidean surfaces.
Java reference: NONE — Java has the polygon + period matrix
pieces but does not assemble them into
a Fuchsian-group representation.
@@ -327,6 +407,9 @@ Phase 10 Global uniformization for genus g ≥ 2
10c' Optional Java-port additions (low priority)
→ KoebePolyhedron.java (321 lines) — Koebe-Andreev-Thurston
circle packings. Adds a fifth DCE method.
Rigidity: Bowers, Bowers, Lutz 2026 "Rigidity of circle polyhedra
and hyperideal polyhedra: the tangency case" (arXiv:2601.22903)
— theoretical uniqueness backing the KAT construction.
→ ElectrostaticSphereFunctional (127 lines) — sphere
distribution baseline.
→ CirclePatternLayout / CirclePatternUtility — face-circle