MCF-stack: Special Solutions of Mean Curvature Flow

Numerical references

This page credits the numerical methods, software, and visual sources used to make the figures in MCF-stack. The mathematical existence and classification references remain with each example and in the bibliography. A newly generated mesh or rendering can still owe its visual conception to another author's picture.

Visual sources and individual credits

The credits below identify documented visual influences and parametrization sources. Where a paper credits an individual illustrator, that credit is retained separately from the paper's authorship. Newly generated schematic geometry is not the source author's numerical mesh.

Höskuldur P. Halldórsson

The planar classification, Sections 2–5 and Figures 4–19, supplies the ODEs and visual references for the annulus-dense shrinkers, rotators, expanding spirals and rotating shrinking spirals. The helicoidal paper, equations (3.3), (4.1) and (5.3), and Figures 1–4, supplies the helicoidal translator ODE and the classical minimal-surface formula attributed there to Wunderlich.

All displayed geometry is newly generated by scripts/generate_halldorsson_geometry.py; no paper figures or source meshes are redistributed. SciPy DOP853 integrates the arclength systems. A scalar Brent solve targets the irrational turning condition; finite precision does not certify irrationality. A comet preset uses finite-radius asymptotic shooting and is explicitly an approximation to the special orbit. Refinement and equation diagnostics are recorded in the geometry audit, without rigorous error bounds. Minimal helicoids are sampled from the exact formula. The viewers apply exact similarity motions to finite patches, and use equal spatial scales. Dashed circles mark accumulation sets, not extra flow components.

David L. Chopp

Chopp's Computation of Self-Similar Solutions for Mean Curvature Flow, Experimental Mathematics 3 (1994), 1–15 supplies the numerical candidates and visual references for the five Chopp entries: Figures 8–12 (cubical), 13–15 (octahedral), 16–19 (saddle), 20–23 (two-handled cone), and 26–28 (four-handled cone). The latter also appears in Angenent–Ilmanen–Chopp, A Computed Example of Nonuniqueness of Mean Curvature Flow in R3 (1995), p. 1943.

Chopp is also credited for Figure 1 in Ilmanen–White, Fattening in Mean Curvature Flow, which informs our two-ended topology drawing, and Figure 2 in Hoffman–Martín–White, a visual reference for the cubical silhouette. Our corresponding models are schematics, not recomputations of Chopp's numerical surfaces. Source review and drawing provenance.

Su–Tsai–Wood: infinite-time Lagrangian neck collapse

The signed-profile time plate and interactive comparison are newly drawn from Su, Tsai and Wood, Infinite-Time Singularities of the Lagrangian Mean Curvature Flow: Section 2.3 gives the Lawlor neck, equation (1.1) gives its leading-order scale dynamics, and Proposition 9.5 identifies the rescaled limit. Figures 1–2 explain the desingularization and compact topology. No paper figure or mesh is copied. The local equal-angle profiles are exact; the time-dependent scaling and global topology diagram illustrate the construction and do not compute the compact flow. Formulas, scope, and reproducibility.

Lee–Wang quadric flow

The shrinker time plate and circle-action viewer are original drawings from Lee and Wang, Hamiltonian stationary cones and self-similar solutions in higher dimension, Theorem 1.1 and Sections 2–3. They sample the exact unit-weight coordinates in C³; no PDE is solved. The displayed phase leaves and projected orbit curves are labeled as such. The SVG and browser canvas use the same coordinate generator, with a fixed ambient crop and scale across times. No figure, mesh, or software from the paper is reproduced.

The companion expander illustration samples the exact real slices x₃ = ±√(x₁² + x₂² + 2t) at positive times and the singular cone at t = 0. The comparison keeps one spatial scale and a fixed radial display cutoff. Its circle-orbit diagram is drawn in the exact two-plane spanned by x and i(x₁,x₂,−x₃) in R⁶; changing the circle phase keeps flow time fixed. These real slices are not themselves mean curvature flows in R³. See the expander geometry and verification notes.

Mario B. Schulz

The illustration for the work of Reto Buzano, Huy The Nguyen, and Mario B. Schulz follows the qualitative geometry of Section 4, Figures 3–4 of Noncompact self-shrinkers for mean curvature flow with arbitrary genus, version 2. These are visual references as well as mathematical source material. The authors produced their simulations with Kenneth Brakke's Surface Evolver. Our mesh instead samples an illustrative implicit field. BNS drawing provenance.

Schulz is individually credited for Figure 5, the genus-five numerical picture in Hoffman–Martín–White, Generating Shrinkers by Mean Curvature Flow, version 3. It informs our sphere–plane drawing and its interior view, together with Torralbo's figures below.

Schulz's Geometric Analysis Gallery, especially its self-shrinker collection, is an additional resource for these visualizations. The documented sources used for our drawings are the paper figures identified above; the gallery link does not assert that the website itself was consulted during the original implementation, or that its images or meshes were reused.

Ao Sun: supplied Chu–Sun numerical replay pages

The two supplementary Chu–Sun experiment viewers were supplied by Ao Sun with their numerical-note and archive provenance retained. Both use three.js 0.128.0; the first also uses pako 2.1.0 to decompress stored frames. These are replays of supplied computations, not numerical experiments independently reproduced by the website integration. See the integration and provenance record and the retained three.js and pako license notices. Private notes and solver archives are not exported.

Other source-specific drawing references

Other figures use the source paper's profiles or construction diagrams. Examples include Drugan's Figure 1, Møller's Figures 1–2, Nguyen's Figure 1, and the planar-network diagrams reviewed for the expander picture. Their exact roles are recorded in the Drugan, Møller, Nguyen, and network provenance notes. The figure documentation supplies further source locators; this page does not replace the individual example references.

Drawing methods and their scope

  • Formula sampling and projection. Parametrizations are sampled into curves or triangles. Revolving a profile, taking a slice, or projecting from a higher-dimensional ambient space is identified in the caption. The mesh is a finite representation of the formula.
  • Numerical ODE profiles. SciPy integration and, where required, Brent root finding produce profiles with closing or matching conditions. DOP853 is used in several generators. The interactive Abresch–Langer viewer also has a custom period quadrature and bisection implementation. Solver settings and residuals are recorded in the relevant code and audit.
  • Numerical PDE and flow models. Selected generators use finite differences, sparse linear solves, or truncated linearized evolution. Their specific discretizations and limitations accompany the figures. A finite-domain calculation or linearized perturbation is not automatically a computed complete soliton or nonlinear ancient flow.
  • Implicit schematic meshes. Marching cubes extracts a surface from a sampled drawing field; quadric simplification reduces its triangle count. Connectivity, boundary loops, and Euler characteristic are checked where recorded. These checks describe the displayed mesh and do not establish the shrinker equation.
  • Rendering. Custom Python and JavaScript code produces SVG plates and Canvas/WebGL viewers with projection, shading, rotation, zoom, and cutaways. The supplied Chu–Sun replay pages additionally use three.js. Pillow supplies raster panels in selected plates; trimesh supplies selected mesh operations. Cutaway edges and finite display rims are explained in the captions.

The references below credit implemented algorithms and software dependencies; they are not a claim that every listed publication was read during every figure's original creation. Surface Evolver is credited for the source simulations that informed our schematics, rather than as a tool used to generate those MCF-stack meshes.

Methods and software references

Entries are sorted automatically by structured author names, then year and title. Each entry explains its role. Software documentation links were checked on 8 November 2026; this date does not identify the versions used for earlier asset generation.

[BarberDobkinHuhdanpaa1996]

C. Bradford Barber, David P. Dobkin, and Hannu Huhdanpaa. The Quickhull algorithm for convex hulls. ACM Transactions on Mathematical Software, 22(4):469–483, 1996. doi:10.1145/235815.235821.

Method behind Qhull, used through SciPy's Delaunay and ConvexHull routines in selected stacking, doubling, and other triangulated models.

[Brakke1992]

Kenneth A. Brakke. The surface evolver. Experimental Mathematics, 1(2):141–165, 1992. URL: https://www.kenbrakke.com/evolver/, doi:10.1080/10586458.1992.10504253.

Source-side software credit: Buzano, Nguyen, and Schulz used Surface Evolver for their numerical illustrations. MCF-stack's corresponding schematic is generated from its own drawing field; it does not reproduce their Evolver calculation.

[FastSimplification]

fast-simplification contributors. fast-simplification: python wrapper for Fast-Quadric-Mesh-Simplification. Software documentation; accessed 8 November 2026. URL: https://pyvista.github.io/fast-simplification/.

Implementation used to reduce triangle counts for interactive figures. Credit also belongs to the wrapped Fast-Quadric-Mesh-Simplification project by sp4cerat and contributors; its repository is linked in the documentation. This is distinct from using PyVista as a renderer.

[GarlandHeckbert1997]

Michael Garland and Paul S. Heckbert. Surface simplification using quadric error metrics. In Proceedings of SIGGRAPH 1997, 209–216. 1997. URL: https://www.cs.cmu.edu/~garland/quadrics/.

Underlying quadric-error idea for mesh simplification. The software actually called by the drawing generators is fast-simplification, sometimes through trimesh.

[HairerNorsettWanner1993]

Ernst Hairer, Syvert P. Nørsett, and Gerhard Wanner. Solving Ordinary Differential Equations I: Nonstiff Problems. Springer, 2 edition, 1993. doi:10.1007/978-3-540-78862-1.

Reference for numerical ODE integration, including the DOP853 method cited by SciPy. Several rotational profiles use solve_ivp with DOP853; other generators explicitly choose different solvers.

[HarrisEtAl2020]

Charles R. Harris, K. Jarrod Millman, Stéfan J. van der Walt, and others. Array programming with NumPy. Nature, 585:357–362, 2020. doi:10.1038/s41586-020-2649-2.

NumPy supplies coordinate arrays, sampling grids, vector operations, normals, and transformations throughout the numerical geometry generators.

[KhronosWebGL]

Khronos WebGL Working Group. WebGL specification, version 1.0. Web standard; accessed 8 November 2026. URL: https://registry.khronos.org/webgl/specs/latest/1.0/.

Browser graphics interface used by the project's custom interactive surface viewers, including depth testing, lighting, and cutaway rendering. This credits the rendering platform rather than a surface construction.

[LewinerEtAl2003]

Thomas Lewiner, Hélio Lopes, Antônio Wilson Vieira, and Geovan Tavares. Efficient implementation of marching cubes' cases with topological guarantees. Journal of Graphics Tools, 8(2):1–15, 2003. URL: https://thomas.lewiner.org/pub/marching_cubes_jgt.html, doi:10.1080/10867651.2003.10487582.

Marching-cubes variant used by skimage.measure.marching_cubes to extract meshes from sampled scalar fields. Its topology guarantees concern the extraction algorithm; they do not certify that an illustrative field solves a geometric PDE.

[Melko2010]

O. Michael Melko. Visualizing minimal surfaces. The Mathematica Journal, 2010. URL: https://www.mathematica-journal.com/2010/12/22/visualizing-minimal-surfaces/.

Equations (16)--(19), particularly (17), supply the stationary Costa parametrization used in the ancient-Costa illustration. MCF-stack implements its evaluation and mesh itself; the displayed normal perturbation is a separate truncated linearized model. No Mathematica package or source image is included.

[Pako]

pako contributors. pako: javascript compression library. Version 2.1.0; software project. URL: https://github.com/nodeca/pako/tree/2.1.0.

Developed by Andrey Tupitsin and Vitaly Puzrin, porting zlib by Jean-loup Gailly and Mark Adler. Used to decompress stored frame data in the first supplied Chu--Sun numerical replay; it is not a geometry solver. The upstream project distinguishes its MIT license from the zlib license of the ported core.

[Pillow]

Pillow contributors. Pillow: python imaging library fork. Software project; accessed 8 November 2026. URL: https://python-pillow.org/.

Used by selected figure generators to draw and encode raster views, including raster panels embedded in otherwise vector SVG plates.

[ThreeJS]

three.js authors. three.js: javascript 3D library. Version 0.128.0 (r128); software project. URL: https://github.com/mrdoob/three.js/tree/r128.

The two supplementary Chu--Sun numerical replay pages supplied by Ao Sun use this locally hosted library for their surface rendering. Its MIT license is retained beside the bundled library. This dependency is separate from the catalogue's custom Canvas and WebGL viewers.

[Trimesh]

trimesh contributors. trimesh. Software documentation; accessed 8 November 2026. URL: https://trimesh.org/.

Used for mesh processing, normals, simplification, and combinatorial topology checks in the genus-labelled sphere--torus schematics. Such checks concern the exported triangulation, not the shrinker PDE.

[VanDerWaltEtAl2014]

Stéfan van der Walt, Johannes L. Schönberger, Juan Nunez-Iglesias, François Boulogne, Joshua D. Warner, Neil Yager, Emmanuelle Gouillart, Tony Yu, and the scikit-image contributors. scikit-image: image processing in Python. PeerJ, 2:e453, 2014. doi:10.7717/peerj.453.

Software credit for the library providing marching_cubes, in addition to the algorithm credit to Lewiner and coauthors.

[VirtanenEtAl2020]

Pauli Virtanen, Ralf Gommers, Travis E. Oliphant, and others. SciPy 1.0: fundamental algorithms for scientific computing in Python. Nature Methods, 17:261–272, 2020. doi:10.1038/s41592-019-0686-2.

SciPy supplies ODE integration, root finding, interpolation, sparse linear algebra, eigenvalue calculations, special functions, and triangulation for the generators that call those routines. A software citation does not certify a computed solution.

[WHATWGCanvas]

WHATWG. HTML standard: the canvas element. Web standard; accessed 8 November 2026. URL: https://html.spec.whatwg.org/multipage/canvas.html.

Canvas 2D is the browser drawing interface used by the custom curve and surface viewers that project, shade, and draw geometry in JavaScript.

[W3CSVG]

World Wide Web Consortium. Scalable vector graphics (SVG) 2. Web standard; accessed 8 November 2026. URL: https://www.w3.org/TR/SVG2/.

SVG supplies the static, printable figure format, including labels, paths, triangles, and occasional embedded raster panels.

Code, provenance, and attribution

The figure-generation scripts, viewer code and geometry assets, and figure provenance notes distinguish source formulas from drawing choices and record numerical settings where available. The figure registry connects these assets to the catalogue. Public links point to original publications; supplied PDFs and private research files are not redistributed.

For attribution, retain the named visual source and figure locator, the numerical method or schematic construction, and the implementation credit. “Original” in older captions refers to newly generated geometry or rendering and should not be read as an absence of visual influence. A shared shape or topology does not identify surfaces produced by different mathematical constructions.

The reading site's infrastructure acknowledgments remain in the project README, with the original infrastructure license preserved.

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