Finding-U3 from doc/reviewer/usability-audit-2026-05-31.md.
Three concrete errors corrected:
1. check_gauss_bonnet() row (was: implies all map types work)
→ now: 'EuclideanMaps/SphericalMaps only' — HyperIdealMaps overload
is = delete (compile error since external-audit Finding-B fix)
2. enforce_gauss_bonnet() row (same issue)
→ same restriction note added
3. newton_hyper_ideal() preconditions (was: 'lambda0 initialised')
→ WRONG: HyperIdeal computes lengths from b_v, a_e via zeta functions
internally; lambda0 plays no role. Correct precondition:
'no lambda0 needed · no GB pre-check'
→ Added explanation: strictly convex energy (Springborn 2020 Thm 1.3)
→ Newton converges for any targets without a pre-check
Gauss-Bonnet prose section also updated:
- Examples now show EuclideanMaps/SphericalMaps explicitly
- HyperIdeal compile-error note added with the correct hyperbolic
identity Σ(2π-Θ_v) - Area = 2π·χ and why no pre-check is needed
- Open-mesh note added (GB identity does not hold for boundary meshes)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
b8d6e23adf