fix(citations): correct Kolpakov-Mednykh misattribution → Springborn 2008

arXiv:math/0603097 is Springborn 2008 ("A variational principle for weighted
Delaunay triangulations and hyperideal polyhedra"), not a Kolpakov-Mednykh paper.
The author pair Kolpakov & Mednykh has no joint publication from 2006; their
earliest collaboration is arXiv:1008.0312 (2010, on torus knots, unrelated).

The wrong author name was introduced during the Java→C++ port — the Java source
correctly links to math/0603097 without naming the authors; whoever ported it
invented "Kolpakov-Mednykh". The S1 citation audit (2026-05-31) then cemented
the error by adding the incorrect row to references.md.

Files corrected (7):
- code/include/hyper_ideal_utility.hpp
- code/include/hyper_ideal_functional.hpp
- code/tests/cgal/test_hyper_ideal_functional.cpp
- doc/math/references.md
- doc/roadmap/research-track.md
- doc/architecture/project-structure.md
- doc/api/tests.md

Also:
- doc/reviewer/math-derivation-citation-audit-2026-05-31.md: M1 post-correction noted
- doc/reviewer/finding-orchestration.md: lesson-learned section added (AI citation
  audits can introduce plausible-but-wrong attributions; human expert review required
  before CGAL submission)
- papers/MANUAL-DOWNLOAD.md: overview of papers requiring manual download (paywalled
  journals, TU Berlin theses, books)
- .gitignore: papers/*.pdf excluded (downloaded arXiv PDFs, not tracked)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

doc/api/tests.md

@@ -7,7 +7,7 @@ Pure-math tests, only Eigen required. Covers Java utilities ported in Phase 1–
 | File | What it tests |
 |---|---|
 | `test_clausen.cpp` | Clausen Cl₂, Lobachevsky Л, ImLi₂ — values at known points |
-| `test_hyper_ideal_utility.cpp` | Tetrahedron volumes (Meyerhoff / Kolpakov–Mednykh) + Java golden-value oracle (Clausen/Л/ImLi₂, ζ₁₃/₁₄/₁₅/ζ, both volume formulas) |
+| `test_hyper_ideal_utility.cpp` | Tetrahedron volumes (Meyerhoff / Springborn 2008) + Java golden-value oracle (Clausen/Л/ImLi₂, ζ₁₃/₁₄/₁₅/ζ, both volume formulas) |
 | `test_matrix_utility.cpp` | Matrix helpers |
 | `test_surface_curve_utility.cpp` | Surface curve utilities |
 | `test_discrete_elliptic_utility.cpp` | Discrete elliptic functions |

doc/architecture/project-structure.md

@@ -14,7 +14,7 @@ ConformalLabpp/
 │   │   ├── constants.hpp             # conformallab::PI, TWO_PI
 │   │   ├── clausen.hpp               # Cl₂, Lobachevsky Л, ImLi₂
 │   │   ├── hyper_ideal_geometry.hpp  # ζ₁₃/₁₄/₁₅, lᵢⱼ, αᵢⱼ, σᵢ, σᵢⱼ
-│   │   ├── hyper_ideal_utility.hpp   # Tetrahedron volumes (Meyerhoff / Kolpakov–Mednykh)
+│   │   ├── hyper_ideal_utility.hpp   # Tetrahedron volumes (Meyerhoff / Springborn 2008)
 │   │   ├── hyper_ideal_visualization_utility.hpp  # Poincaré disk projection, circumcircle helpers
 │   │   ├── hyper_ideal_functional.hpp # HyperIdeal energy + gradient on ConformalMesh
 │   │   ├── hyper_ideal_hessian.hpp   # HyperIdeal Hessian (symmetric FD, Phase 9b: analytic)

doc/math/references.md

@@ -29,7 +29,7 @@ Java reference implementation: [github.com/varylab/conformallab](https://github.
 | Reference | Used in |
 |---|---|
 | ✅ **Springborn** — *Ideal Hyperbolic Polyhedra and Discrete Uniformization*, Discrete & Computational Geometry **64** (2020), pp. 63–108. DOI: [10.1007/s00454-019-00132-8](https://doi.org/10.1007/s00454-019-00132-8) | `hyper_ideal_geometry.hpp` — ζ₁₃/ζ₁₄/ζ₁₅ functions; `hyper_ideal_functional.hpp` |
-| ✅ **Kolpakov, Mednykh** — *A Formula for the Volume of a Hyperbolic Tetrahedron*, arXiv: [math/0603097](https://arxiv.org/abs/math/0603097) (2006) | Tetrahedron volume with one ideal vertex: `calculateTetrahedronVolumeWithIdealVertexAtGamma` in `hyper_ideal_utility.hpp` (Phase 9b analytic Hessian) |
+| ✅ **Springborn** — *A variational principle for weighted Delaunay triangulations and hyperideal polyhedra*, J. Differential Geometry **78**(2) (2008), pp. 333–367. arXiv: [math/0603097](https://arxiv.org/abs/math/0603097) | Tetrahedron volume with one ideal vertex: `calculateTetrahedronVolumeWithIdealVertexAtGamma` in `hyper_ideal_utility.hpp` (Phase 9b analytic Hessian). ⚠️ *Korrektur:* war fälschlich als „Kolpakov–Mednykh 2006" zitiert — dieses Autorenpaar hat 2006 kein gemeinsames Paper veröffentlicht. Die Java-Quelle verlinkt korrekt auf math/0603097 (= Springborn 2008); der falsche Autorenname wurde beim C++-Port hinzugefügt.* |
 | ✅ **Meyerhoff, Ushijima** — *A Note on the Dirichlet Domain*, in: The Epstein Birthday Schrift (2006) | Tetrahedron volume with three ideal vertices: `calculateTetrahedronVolumeFullyIdeal` in `hyper_ideal_utility.hpp` |
 | **Pinkall, Polthier** — *Computing Discrete Minimal Surfaces and Their Conjugates*, Experimental Mathematics (1993) | `euclidean_hessian.hpp` — cotangent Laplacian |
 | **Bobenko, Springborn** — *Variational Principles for Circle Patterns and Koebe's Theorem*, Transactions AMS (2004) | Variational angle-sum framework underlying all three functionals |

doc/reviewer/finding-orchestration.md

@@ -59,7 +59,7 @@ Status: ✅ done · ⬜ open (actionable) · ⏸ deferred (intentional) · ⛔ b
 | V3 | input-val | 🟡 | ✅ | Sonnet | S1 |
 | C1 | test-cov | 🔴 | ✅ | Sonnet | S1 |
 | N4, N6 | numerics | 🟡/🔵 | ✅ | Haiku | S1 |
-| M1, M2, M4 | math-cite | 🟡/🔵 | ✅ | Haiku | S1 |
+| M1, M2, M4 | math-cite | 🟡/🔵 | ✅⚠️ | Haiku → re-fix 2026-06-04 | S1 + nachkorrigiert |
 | C2, C3 | test-cov | 🔴 | ✅ | Sonnet | S1 |
 | V1, V2, V4 | input-val | 🟡 | ✅ | Sonnet | S1 |
 | I2, I3, I4 | test-cov | 🟡 | ✅ | Sonnet | S1 |
@@ -166,6 +166,42 @@ Gated by the author's reply on porting/relicensing rights.
 ### 👤 Out of model scope
 - **M5** — the large hand-derivations need a domain-expert prose review
   (the numerical results are already validated; the prose is not).
+- **Alle Zitationen** — alle `references.md`-Einträge müssen von einem
+  Fachexperten manuell verifiziert werden (siehe Lektion unten).
+
+---
+
+## ⚠️ Lektion: KI-gestützte Citation-Audits können Fehler einführen
+
+**Datum:** 2026-06-04  
+**Befund:** Die M1-Auflösung in S1 (Haiku, 2026-05-31) war selbst fehlerhaft:
+
+- Der Haiku-Audit erkannte korrekt, dass `Kolpakov–Mednykh` in `references.md` fehlt
+- Als „Fix" wurde die Zeile mit arXiv:math/0603097 ergänzt — aber **math/0603097 ist Springborn 2008**, nicht Kolpakov–Mednykh
+- Das Autorenpaar „Kolpakov & Mednykh" hat **2006 kein gemeinsames Paper veröffentlicht** (früheste Zusammenarbeit: 2010, über Torusknoten, nicht Tetraedervolumen)
+- Der falsche Autorenname entstand bereits beim Java→C++-Port; der Audit hat ihn zementiert statt korrigiert
+
+**Nachkorrektur:** 2026-06-04, 7 Dateien korrigiert (Code-Kommentare, references.md, roadmap, architecture-doc, tests-doc, audit-doc).
+
+**Konsequenz für das Projekt:**
+
+> KI-Modelle können bei Citation-Audits plausibel klingende aber falsche  
+> Autoren/Jahres-Zuordnungen produzieren — besonders wenn die Primärquelle  
+> (Java-Code) nur einen Link ohne Autorennamen enthält.
+
+**Empfehlung:**
+
+Vor jeder öffentlichen Veröffentlichung / CGAL-Submission müssen **alle** Einträge
+in `references.md` von einem **Fachexperten (Mensch)** gegen die tatsächlichen
+Papiere verifiziert werden:
+
+| Priorität | Was prüfen |
+|---|---|
+| 🔴 Hoch | Formeln in Code-Kommentaren (`hyper_ideal_utility.hpp`, `hyper_ideal_functional.hpp`) gegen die zitierten Paper |
+| 🔴 Hoch | Meyerhoff / Ushijima — Buchkapitel, nie direkt verifiziert |
+| 🟡 Mittel | Ob Springborn 2008 (math/0603097) die 12-Term-Lobachevsky-Formel tatsächlich enthält |
+| 🟡 Mittel | M3: post-2023 / arXiv-only Zitationen (Bowers-Bowers-Lutz 2026 etc.) |
+| 🔵 Niedrig | Alle weiteren `references.md`-Einträge auf Titel/Jahr/DOI-Konsistenz |
 
 ---
 

doc/reviewer/math-derivation-citation-audit-2026-05-31.md

@@ -16,6 +16,16 @@ Status legend: 🔴 Critical · 🟡 Important · 🔵 Polish
 > future-dated/arXiv citations) **open** → S4; **M5** (prose derivation review)
 > needs a **domain expert** (out of model scope). See
 > [`finding-orchestration.md`](finding-orchestration.md).
+>
+> **⚠️ M1 Nachkorrektur (2026-06-04):** Die ursprüngliche M1-Auflösung war selbst
+> fehlerhaft — arXiv:math/0603097 ist **Springborn 2008** (*A variational principle
+> for weighted Delaunay triangulations and hyperideal polyhedra*), nicht
+> Kolpakov–Mednykh. Kolpakov und Mednykh haben 2006 kein gemeinsames Paper
+> veröffentlicht (früheste Zusammenarbeit: 2010). Der falsche Autorenname wurde beim
+> Java→C++-Port erfunden; die Java-Quelle verlinkt korrekt auf math/0603097 ohne
+> Autorennamen. Korrekturen angewendet in: `hyper_ideal_utility.hpp`,
+> `hyper_ideal_functional.hpp`, `test_hyper_ideal_functional.cpp`,
+> `doc/math/references.md`.
 
 > **Good news up front:** `doc/math/references.md` is unusually scholarly and already
 > contains several *self-corrections* (the Glickenstein "eq. (4.6)" numbering fix →

doc/roadmap/research-track.md

@@ -145,10 +145,10 @@ The phase numbers match `doc/roadmap/phases.md`.
 ### Hyper-ideal volume formulas for 2- and 3-ideal-vertex faces (Phase 9b+, 🔲 planned)
 
 * **Mathematical sources:**
-  - **Kolpakov, A. & Mednykh, A.** (2012). *Spherical structures on torus
-    knots and links.* Sibirsk. Mat. Zh. 53(3), 535–541 — see the earlier
-    arXiv:math/0603097 for the one-ideal-vertex formula already implemented
-    as `calculateTetrahedronVolumeWithIdealVertexAtGamma`.
+  - **Springborn, B.** (2008). *A variational principle for weighted Delaunay
+    triangulations and hyperideal polyhedra.* J. Differential Geometry **78**(2),
+    333–367. arXiv:math/0603097 — the source of the one-ideal-vertex formula
+    already implemented as `calculateTetrahedronVolumeWithIdealVertexAtGamma`.
   - **Milnor, J.** (1982). *Hyperbolic geometry: The first 150 years.*
     Bull. Amer. Math. Soc. 6(1), 9–24.  → Volume of an ideal tetrahedron
     via Clausen function; this is the all-ideal case with 4 ideal vertices.
@@ -175,10 +175,10 @@ The phase numbers match `doc/roadmap/phases.md`.
 
 * **Acceptance criteria:**
   - Identify the correct formula for a hyper-ideal tetrahedron with exactly
-    2 ideal vertices from the literature (check Kolpakov-Mednykh generalisations
+    2 ideal vertices from the literature (check Springborn 2008 §3–4 generalisations
     and Vinberg orthoscheme decomposition).
   - Implement `calculateTetrahedronVolumeWithTwoIdealVertices(…)` analogous
-    to the existing Kolpakov-Mednykh function.
+    to the existing Springborn 2008 one-ideal-vertex function.
   - Implement `calculateTetrahedronVolumeWithThreeIdealVertices(…)` (one
     hyper-ideal + three ideal = fully cusp-like case).
   - Replace the `throw std::logic_error` in `face_energy()` with the correct