pith. sign in

arxiv: 2510.23757 · v2 · submitted 2025-10-27 · 🧮 math.DG · math.CV· math.GT

Discrete minimal surfaces: Old and New

Pith reviewed 2026-05-18 02:47 UTC · model grok-4.3

classification 🧮 math.DG math.CVmath.GT
keywords discrete minimal surfacescircle patternsdiscrete Weierstrass representationTeichmüller theorypolyhedral surfacesmean curvaturevariational characterizationdiscrete differential geometry
0
0 comments X

The pith

All simply connected discrete minimal surfaces arise from circle patterns via a discrete Weierstrass representation formula.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This survey examines structure-preserving discretizations of minimal surfaces in Euclidean space, with emphasis on one defined by parallel face offsets of polyhedral surfaces. That choice produces a natural discrete notion of vanishing mean curvature together with a variational characterization. The central result states that every simply connected surface of this type can be built from a circle pattern by means of a discrete Weierstrass representation formula. The same formula identifies the space of such surfaces with the deformation space of circle patterns, thereby embedding the discrete theory inside classical Teichmüller theory. Several variants that alter the curvature definition or replace circle-pattern data with other discrete structures are also reviewed.

Core claim

The discretization of minimal surfaces via parallel face offsets of polyhedral surfaces yields a natural notion of vanishing mean curvature that admits a variational characterization. All simply connected discrete minimal surfaces of this type can be constructed from circle patterns by a discrete Weierstrass representation formula; this representation identifies the space of discrete minimal surfaces with the deformation space of circle patterns and therefore with classical Teichmüller theory.

What carries the argument

The discrete Weierstrass representation formula that converts circle-pattern data into discrete minimal surfaces.

If this is right

  • The space of discrete minimal surfaces is parametrized by the deformation space of circle patterns.
  • Classical tools from Teichmüller theory become available for studying existence, uniqueness, and moduli of discrete minimal surfaces.
  • Variants obtained by changing the mean-curvature definition or by using circle packings and factorized cross ratios supply alternative discrete models.
  • Open questions listed at the end indicate concrete directions for extending the theory to non-simply-connected surfaces or to other ambient geometries.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The link to circle patterns suggests that discrete minimal surfaces could be generated computationally by solving circle-pattern optimization problems rather than by direct curvature minimization.
  • The same correspondence may yield discrete versions of classical theorems, such as the Bernstein theorem or the Weierstrass-Enneper representation, that can be tested on finite meshes.
  • Because the construction is variational, it may admit natural extensions to discrete minimal surfaces with prescribed boundary or with obstacles.

Load-bearing premise

The parallel-face-offset definition of a polyhedral surface produces a discretization whose mean curvature vanishes in a variational sense.

What would settle it

An explicit example of a simply connected discrete minimal surface that cannot be recovered from any circle pattern by the discrete Weierstrass formula would refute the construction claim.

Figures

Figures reproduced from arXiv: 2510.23757 by Masashi Yasumoto, Wai Yeung Lam.

Figure 1
Figure 1. Figure 1: A classical minimal surface in R 3 . This is called En￾neper’s minimal surface. 2.2. Weierstrass representation. To relate minimal surfaces to complex analy￾sis, we consider minimal surfaces under conformal parametrization. A parametrization of a surface f(u, v) is conformal if ⟨fu, fv⟩ = 0 and ∥fu∥ 2 = ∥fv∥ 2 , or equivalently the first fundamental form I is a diagonal matrix with equal diagonal entries. … view at source ↗
Figure 2
Figure 2. Figure 2: Two discrete minimal surfaces satisfying Definition 3.1, both reminiscent of the classical Enneper minimal surface. where nr, nl are unit normals of the right face and the left face of the oriented edge from i to j. Definition 3.1. Given a polyhedral surface f : M∗ → R 3 , its integrated mean curvature H : F ∗ → R is defined for every face ϕ ∈ F ∗ by Hϕ = 1 2 X ij∈∂ϕ ℓij tan αij 2 , where the sum is over a… view at source ↗
Figure 3
Figure 3. Figure 3: A circle pattern with constant intersection angles Θ = π/3. Definition 3.5. Let g : V → C be a non-degenerate realization in C. A real-valued function q : E → R defined on the set of all edges E is called a discrete holomorphic quadratic differential if it satisfies for all vertices i ∈ V X j qij = 0 , X j qij gj − gi = 0 (4) where the sum is taken over all vertices j adjacent to i. One can verify directly… view at source ↗
Figure 4
Figure 4. Figure 4: A circle pattern with complex cross ratio Xij = − (gk−gi)(gl−gj ) (gi−gl)(gj−gk) . The intersection angle of the circumcircles of tri￾angles {ijk} and {jil} is given by Θij = arg(Xij ). Proposition 3.7. Up to M¨obius transformations, the space of circle patterns on the Riemann sphere with prescribed intersection angles Θ can be parametrized by complex cross ratios P(Θ) := {X : E → C | Im(log X) = Θ and X s… view at source ↗
Figure 5
Figure 5. Figure 5: A discrete minimal surface which is a realization of a topological sphere and each face has self-intersection. Its Gauss map fails to be locally convex. Indeed, the Gauss map is Jessen’s orthogonal icosahedron, which is known to possess a non-trivial infinitesimal isometric deformation. 4. Variants of discretization Among the many possible discretizations, a central challenge in discrete differen￾tial geom… view at source ↗
Figure 6
Figure 6. Figure 6: An isothermic surface and its curvature lines. Each infinitesimal quadrilateral bounded by curvature lines becomes an infinitesimal square. With the Christoffel transformation, a minimal surface can be characterized without referring to mean curvature. Proposition 4.2. A surface f is minimal if and only if it is isothermic and its Christoffel transform f ∗ coincides with its Gauss map to the sphere. Follow… view at source ↗
Figure 7
Figure 7. Figure 7: A discrete isothermic surface that is minimal. The picture differs from the left picture in [PITH_FULL_IMAGE:figures/full_fig_p016_7.png] view at source ↗
read the original abstract

We survey structure-preserving discretizations of minimal surfaces in Euclidean space. Our focus is on a discretization defined via parallel face offsets of polyhedral surfaces, which naturally leads to a notion of vanishing mean curvature and a corresponding variational characterization. All simply connected discrete minimal surfaces of this type can be constructed from circle patterns via a discrete Weierstrass representation formula. This representation links the space of discrete minimal surfaces to the deformation space of circle patterns, and thereby to classical Teichm\"uller theory. We also discuss variants of discrete minimal surfaces obtained by modifying the definition of mean curvature, restricting the variational criterion, or replacing circle pattern data with discrete conformal equivalence, Koebe-type circle packings, or quadrilateral meshes with factorized cross ratios. We conclude with open questions on discrete minimal surfaces.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The manuscript surveys structure-preserving discretizations of minimal surfaces in Euclidean space. Its focus is a discretization via parallel face offsets of polyhedral surfaces that induces a notion of vanishing mean curvature together with a variational characterization. The central claim is that all simply connected discrete minimal surfaces of this type arise from circle patterns through a discrete Weierstrass representation formula; this representation is said to link the surfaces to the deformation space of circle patterns and thereby to classical Teichmüller theory. Variants obtained by altering the mean-curvature definition, restricting the variational criterion, or substituting other discrete data (discrete conformal equivalence, Koebe packings, factorized cross-ratio quadrilaterals) are discussed, and the paper closes with open questions.

Significance. If the claimed surjectivity of the discrete Weierstrass map holds, the survey would supply a complete classification of simply connected discrete minimal surfaces in terms of circle-pattern deformation spaces, thereby furnishing a concrete bridge between discrete differential geometry and Teichmüller theory. The organizational overview of existing constructions and the explicit listing of open problems constitute additional value for the field.

major comments (2)
  1. [Abstract / §3] Abstract and the statement of the main theorem (presumably §3): the claim that 'all simply connected discrete minimal surfaces of this type can be constructed from circle patterns' asserts surjectivity of the discrete Weierstrass map. The forward direction is standard, but the converse—that every parallel-offset surface with vanishing mean curvature arises from some circle pattern—requires a completeness argument for the deformation space or a verification that global closing conditions are automatically satisfied. No explicit reference or derivation addressing this direction appears in the overview; without it the universal quantifier remains unsubstantiated.
  2. [§2] §2 (definition of the discretization): the assertion that parallel face offsets 'naturally lead to' a notion of vanishing mean curvature and a corresponding variational characterization is stated without an explicit formula for the discrete mean curvature or a derivation showing that the variational critical points coincide with the offset condition. This step is load-bearing for all subsequent claims that rely on the variational principle.
minor comments (2)
  1. Notation for the discrete Weierstrass data (edge lengths, radii, or cross ratios) should be introduced with a single consistent table or diagram early in the text to aid readability across the variants discussed later.
  2. A brief comparison table listing the different mean-curvature definitions and their associated variational principles would clarify the distinctions among the variants presented in the later sections.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful reading and constructive comments. We address the two major points below and indicate planned revisions to strengthen the exposition.

read point-by-point responses
  1. Referee: [Abstract / §3] Abstract and the statement of the main theorem (presumably §3): the claim that 'all simply connected discrete minimal surfaces of this type can be constructed from circle patterns' asserts surjectivity of the discrete Weierstrass map. The forward direction is standard, but the converse—that every parallel-offset surface with vanishing mean curvature arises from some circle pattern—requires a completeness argument for the deformation space or a verification that global closing conditions are automatically satisfied. No explicit reference or derivation addressing this direction appears in the overview; without it the universal quantifier remains unsubstantiated.

    Authors: The forward direction is indeed immediate from the discrete Weierstrass formula. For the converse, the simply-connected assumption together with the variational characterization ensures that the global closing conditions are satisfied once local consistency with the circle pattern is achieved; this follows from the completeness of the deformation space of circle patterns on the sphere (or disk) as established in the Teichmüller-theoretic literature. We will add a concise paragraph in §3 sketching this argument and citing the relevant completeness result for circle-pattern deformation spaces. revision: yes

  2. Referee: [§2] §2 (definition of the discretization): the assertion that parallel face offsets 'naturally lead to' a notion of vanishing mean curvature and a corresponding variational characterization is stated without an explicit formula for the discrete mean curvature or a derivation showing that the variational critical points coincide with the offset condition. This step is load-bearing for all subsequent claims that rely on the variational principle.

    Authors: We agree that an explicit formula and short derivation would improve readability. The discrete mean curvature is given by the trace of the discrete shape operator obtained from the parallel offset, and its vanishing is equivalent to criticality of the discrete area functional under the offset constraint. We will insert the precise formula together with a one-paragraph derivation of the equivalence in the revised §2. revision: yes

Circularity Check

0 steps flagged

No circularity: survey draws on external literature without self-referential reductions

full rationale

This is a survey paper whose central statements, including the discrete Weierstrass representation linking minimal surfaces to circle patterns, are presented as established results from prior literature rather than new derivations internal to the manuscript. The definition of vanishing mean curvature via parallel face offsets is introduced directly from the polyhedral surface construction and leads to a variational characterization without any quoted step that redefines or fits a quantity in terms of itself. No self-citation is load-bearing for a uniqueness theorem or completeness claim within the paper's own equations; the 'all simply connected' assertion is framed as a known correspondence rather than a surjectivity proof reduced to fitted inputs. The derivation chain therefore remains self-contained against external benchmarks.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

This is a survey paper; the central claims rest on definitions and results from prior literature on discrete differential geometry and circle patterns. No new free parameters, axioms, or invented entities are introduced in the abstract.

pith-pipeline@v0.9.0 · 5659 in / 1100 out tokens · 23162 ms · 2026-05-18T02:47:31.070830+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

What do these tags mean?
matches
The paper's claim is directly supported by a theorem in the formal canon.
supports
The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends
The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses
The paper appears to rely on the theorem as machinery.
contradicts
The paper's claim conflicts with a theorem or certificate in the canon.
unclear
Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Reference graph

Works this paper leans on

52 extracted references · 52 canonical work pages

  1. [1]

    Kenmotsu-Bryant type representation formulas for con- stant mean curvature surfaces inH 3(−c2) andS 3 1(c2).Ann

    Reiko Aiyama and Kazuo Akutagawa. Kenmotsu-Bryant type representation formulas for con- stant mean curvature surfaces inH 3(−c2) andS 3 1(c2).Ann. Global Anal. Geom., 17(1):49–75, 1999

  2. [2]

    Discrete isothermic surfaces.J

    Alexander Bobenko and Ulrich Pinkall. Discrete isothermic surfaces.J. Reine Angew. Math., 475:187–208, 1996

  3. [3]

    Bobenko, Ulrike B¨ ucking, and Stefan Sechelmann

    Alexander I. Bobenko, Ulrike B¨ ucking, and Stefan Sechelmann. Discrete minimal surfaces of Koebe type. InModern approaches to discrete curvature, volume 2184 ofLecture Notes in Math., pages 259–291. Springer, Cham, 2017

  4. [4]

    Bobenko, Tim Hoffmann, and Boris A

    Alexander I. Bobenko, Tim Hoffmann, and Boris A. Springborn. Minimal surfaces from circle patterns: geometry from combinatorics.Ann. of Math. (2), 164(1):231–264, 2006

  5. [5]

    Bobenko and Ulrich Pinkall

    Alexander I. Bobenko and Ulrich Pinkall. Discretization of surfaces and integrable systems. InDiscrete integrable geometry and physics (Vienna, 1996), volume 16 ofOxford Lecture Ser. Math. Appl., pages 3–58. Oxford Univ. Press, New York, 1999

  6. [6]

    Bobenko, Ulrich Pinkall, and Boris A

    Alexander I. Bobenko, Ulrich Pinkall, and Boris A. Springborn. Discrete conformal maps and ideal hyperbolic polyhedra.Geom. Topol., 19(4):2155–2215, 2015

  7. [7]

    Bobenko, Helmut Pottmann, and Johannes Wallner

    Alexander I. Bobenko, Helmut Pottmann, and Johannes Wallner. A curvature theory for discrete surfaces based on mesh parallelity.Math. Ann., 348(1):1–24, 2010

  8. [8]

    Bobenko and Yuri B

    Alexander I. Bobenko and Yuri B. Suris.Discrete differential geometry: Integrable structure, volume 98 ofGraduate Studies in Mathematics. American Mathematical Society, Providence, RI, 2008

  9. [9]

    Robert L. Bryant. Surfaces of mean curvature one in hyperbolic space. Number 154-155, pages 12, 321–347, 353. 1987. Th´ eorie des vari´ et´ es minimales et applications (Palaiseau, 1983–1984)

  10. [10]

    Burstall, U

    F. Burstall, U. Hertrich-Jeromin, and W. Rossman. Discrete linear Weingarten surfaces. Nagoya Math. J., 231:55–88, 2018. 18 W.Y. LAM AND M. YASUMOTO

  11. [11]

    On the Surfaces divisible into Squares by their Curves of Curvature.Proc

    Arthur Cayley. On the Surfaces divisible into Squares by their Curves of Curvature.Proc. Lond. Math. Soc., 4:120–121, 1871/73

  12. [12]

    Springer, Cham, 2025

    Joseph Cho, Kosuke Naokawa, Yuta Ogata, Mason Pember, Wayne Rossman, and Masashi Yasumoto.Discrete isothermic surfaces in Lie sphere geometry, volume 2375 ofLecture Notes in Mathematics. Springer, Cham, 2025

  13. [13]

    Conformal geometry of simplicial surfaces

    Keenan Crane. Conformal geometry of simplicial surfaces. InAn excursion through discrete differential geometry, volume 76 ofProc. Sympos. Appl. Math., pages 59–101. Amer. Math. Soc., Providence, RI, 2020

  14. [14]

    Singularities of maximal surfaces.Math

    Shoichi Fujimori, Kentaro Saji, Masaaki Umehara, and Kotaro Yamada. Singularities of maximal surfaces.Math. Z., 259(4):827–848, 2008

  15. [15]

    G´ alvez, Antonio Mart´ ınez, and Francisco Mil´ an

    Jos´ e A. G´ alvez, Antonio Mart´ ınez, and Francisco Mil´ an. Flat surfaces in the hyperbolic 3- space.Math. Ann., 316(3):419–435, 2000

  16. [16]

    Complete linear Weingarten surfaces of Bryant type

    Jos´ e Antonio G´ alvez, Antonio Mart´ ınez, and Francisco Mil´ an. Complete linear Weingarten surfaces of Bryant type. A Plateau problem at infinity.Trans. Amer. Math. Soc., 356(9):3405– 3428, 2004

  17. [17]

    Transformations of discrete isothermic nets and discrete cmc-1 surfaces in hyperbolic space.Manuscripta Math., 102(4):465–486, 2000

    Udo Hertrich-Jeromin. Transformations of discrete isothermic nets and discrete cmc-1 surfaces in hyperbolic space.Manuscripta Math., 102(4):465–486, 2000

  18. [18]

    Cambridge University Press, Cambridge, 2003

    Udo Hertrich-Jeromin.Introduction to M¨ obius differential geometry, volume 300 ofLondon Mathematical Society Lecture Note Series. Cambridge University Press, Cambridge, 2003

  19. [19]

    Hoffmann, W

    T. Hoffmann, W. Rossman, T. Sasaki, and M. Yoshida. Discrete flat surfaces and linear Weingarten surfaces in hyperbolic 3-space.Trans. Amer. Math. Soc., 364(11):5605–5644, 2012

  20. [20]

    Discrete laplacians – spherical and hyperbolic.J

    Ivan Izmestiev and Wai Yeung Lam. Discrete laplacians – spherical and hyperbolic.J. Lond. Math. Soc. (2), 2025

  21. [21]

    On offsets and curvatures for discrete and semidis- crete surfaces.Beitr

    Oleg Karpenkov and Johannes Wallner. On offsets and curvatures for discrete and semidis- crete surfaces.Beitr. Algebra Geom., 55(1):207–228, 2014

  22. [22]

    Maximal surfaces in the 3-dimensional Minkowski spaceL 3.Tokyo J

    Osamu Kobayashi. Maximal surfaces in the 3-dimensional Minkowski spaceL 3.Tokyo J. Math., 6(2):297–309, 1983

  23. [23]

    Maximal surfaces with conelike singularities.J

    Osamu Kobayashi. Maximal surfaces with conelike singularities.J. Math. Soc. Japan, 36(4):609–617, 1984

  24. [24]

    Singularities of flat fronts in hyperbolic space.Pacific J

    Masatoshi Kokubu, Wayne Rossman, Kentaro Saji, Masaaki Umehara, and Kotaro Yamada. Singularities of flat fronts in hyperbolic space.Pacific J. Math., 221(2):303–351, 2005

  25. [25]

    A Weierstrass representation formula for discrete harmonic surfaces.SIGMA Symmetry Integrability Geom

    Motoko Kotani and Hisashi Naito. A Weierstrass representation formula for discrete harmonic surfaces.SIGMA Symmetry Integrability Geom. Methods Appl., 20:Paper No. 034, 15, 2024

  26. [26]

    Kotani, Hisashi

    Motoko. Kotani, Hisashi. Naito, and Toshiaki. Omori. A discrete surface theory.Comput. Aided Geom. Design, 58:24–54, 2017

  27. [27]

    Standard realizations of crystal lattices via harmonic maps.Trans

    Motoko Kotani and Toshikazu Sunada. Standard realizations of crystal lattices via harmonic maps.Trans. Amer. Math. Soc., 353(1):1–20, 2001

  28. [28]

    Discrete minimal surfaces: Critical points of the area functional from inte- grable systems.Int

    Wai Yeung Lam. Discrete minimal surfaces: Critical points of the area functional from inte- grable systems.Int. Math. Res. Not. IMRN, (6):1808–1845, 2018

  29. [29]

    Minimal surfaces from infinitesimal deformations of circle packings.Adv

    Wai Yeung Lam. Minimal surfaces from infinitesimal deformations of circle packings.Adv. Math., 362:106939, 24, 2020

  30. [30]

    Quadratic differentials and circle patterns on complex projective tori.Geom

    Wai Yeung Lam. Quadratic differentials and circle patterns on complex projective tori.Geom. Topol., 25(2):961–997, 2021

  31. [31]

    CMC-1 surfaces via osculating M¨ obius transformations between circle pat- terns.Trans

    Wai Yeung Lam. CMC-1 surfaces via osculating M¨ obius transformations between circle pat- terns.Trans. Amer. Math. Soc., 377(5):3657–3690, 2024

  32. [32]

    Pullback of symplectic forms to the space of circle patterns

    Wai Yeung Lam. Pullback of symplectic forms to the space of circle patterns. 2024

  33. [33]

    Space of circle patterns on tori and its symplectic form

    Wai Yeung Lam. Space of circle patterns on tori and its symplectic form. 2024

  34. [34]

    Holomorphic vector fields and quadratic differentials on planar triangular meshes

    Wai Yeung Lam and Ulrich Pinkall. Holomorphic vector fields and quadratic differentials on planar triangular meshes. InAdvances in discrete differential geometry, pages 241–265. Springer, [Berlin], 2016

  35. [35]

    Isothermic triangulated surfaces.Mathematische An- nalen, 368(1-2):165–195, 2017

    Wai Yeung Lam and Ulrich Pinkall. Isothermic triangulated surfaces.Mathematische An- nalen, 368(1-2):165–195, 2017

  36. [36]

    Trivalent maximal surfaces in minkowski space

    Wai Yeung Lam and Masashi Yasumoto. Trivalent maximal surfaces in minkowski space. In Mar´ ıa A. Ca˜ nadas-Pinedo, Jos´ e Luis Flores, and Francisco J. Palomo, editors,Lorentzian Geometry and Related Topics, Springer Proceedings in Mathematics & Statistics, pages 169–

  37. [37]

    DISCRETE MINIMAL SURFACES: OLD AND NEW 19

    Springer International Publishing, 2017. DISCRETE MINIMAL SURFACES: OLD AND NEW 19

  38. [38]

    Combinatorial Yamabe flow on surfaces.Commun

    Feng Luo. Combinatorial Yamabe flow on surfaces.Commun. Contemp. Math., 6(5):765–780, 2004

  39. [39]

    Lectures on discrete and polyhedral geometry, 2010

    Igor Pak. Lectures on discrete and polyhedral geometry, 2010. Available athttp://www.math. ucla.edu/~pak/book.htm

  40. [40]

    Weierstrass-type representations.Geom

    Mason Pember. Weierstrass-type representations.Geom. Dedicata, 204:299–309, 2020

  41. [41]

    Discrete Weierstrass-type representa- tions.Discrete Comput

    Mason Pember, Denis Polly, and Masashi Yasumoto. Discrete Weierstrass-type representa- tions.Discrete Comput. Geom., 70(3):816–844, 2023

  42. [42]

    Computing discrete minimal surfaces and their conju- gates.Experiment

    Ulrich Pinkall and Konrad Polthier. Computing discrete minimal surfaces and their conju- gates.Experiment. Math., 2(1):15–36, 1993

  43. [43]

    Architectural geometry.Computers & Graphics, 47:145–164, 2015

    Helmut Pottmann, Michael Eigensatz, Amir Vaxman, and Johannes Wallner. Architectural geometry.Computers & Graphics, 47:145–164, 2015

  44. [44]

    A characterization of ideal polyhedra in hyperbolic 3-space.Ann

    Igor Rivin. A characterization of ideal polyhedra in hyperbolic 3-space.Ann. of Math. (2), 143(1):51–70, 1996

  45. [45]

    Discrete linear Weingarten surfaces with singular- ities in Riemannian and Lorentzian spaceforms

    Wayne Rossman and Masashi Yasumoto. Discrete linear Weingarten surfaces with singular- ities in Riemannian and Lorentzian spaceforms. InSingularities in generic geometry, vol- ume 78 ofAdv. Stud. Pure Math., pages 383–410. Math. Soc. Japan, Tokyo, 2018

  46. [46]

    Cambridge University Press, Cambridge,

    Kenneth Stephenson.Introduction to circle packing. Cambridge University Press, Cambridge,

  47. [47]

    The theory of discrete analytic functions

  48. [48]

    Differentialgeometrie des isotropen Raumes

    Karl Strubecker. Differentialgeometrie des isotropen Raumes. III. Fl¨ achentheorie.Math. Z., 48:369–427, 1942

  49. [49]

    Complete surfaces of constant mean curvature 1 in the hyperbolic 3-space.Ann

    Masaaki Umehara and Kotaro Yamada. Complete surfaces of constant mean curvature 1 in the hyperbolic 3-space.Ann. of Math. (2), 137(3):611–638, 1993

  50. [50]

    Maximal surfaces with singularities in Minkowski space.Hokkaido Math

    Masaaki Umehara and Kotaro Yamada. Maximal surfaces with singularities in Minkowski space.Hokkaido Math. J., 35(1):13–40, 2006

  51. [51]

    Infinitesimally flexible meshes and discrete minimal surfaces.Monatsh

    Johannes Wallner and Helmut Pottmann. Infinitesimally flexible meshes and discrete minimal surfaces.Monatsh. Math., 153(4):347–365, 2008

  52. [52]

    Discrete maximal surfaces with singularities in Minkowski space.Differ- ential Geom

    Masashi Yasumoto. Discrete maximal surfaces with singularities in Minkowski space.Differ- ential Geom. Appl., 43:130–154, 2015. Department of Mathematics, University of Luxembourg, 4365 Esch-sur-Alzette, Lux- embourg Email address:wyeunglam@gmail.com Graduate School of Technology, Industrial and Social Sciences, Tokushima Univer- sity, 2-1 Minamijyousanji...