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List of fractals by Hausdorff dimension





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This is an old revision of this page, as edited by Prokofiev2 (talk | contribs)at08:48, 21 March 2014 (Random and natural fractals). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
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According to Falconer, one of the essential features of a fractal is that its Hausdorff dimension strictly exceeds its topological dimension.[1] Presented here is a list of fractals ordered by increasing Hausdorff dimension, with the purpose of visualizing what it means for a fractal to have a low or a high dimension.

Deterministic fractals

Hausdorff dimension
(exact value)
Hausdorff dimension
(approx.)
Name Illustration Remarks
Calculated 0.538 Feigenbaum attractor   The Feigenbaum attractor (see between arrows) is the set of points generated by successive iterations of the logistic function for the critical parameter value  , where the period doubling is infinite. This dimension is the same for any differentiable and unimodal function.[2]
  0.6309 Cantor set   Built by removing the central third at each iteration. Nowhere dense and not a countable set.
  0.6942 Asymmetric Cantor set   The dimension is not  , as would be expected from the generalized Cantor set with γ=1/4, which has the same length at each stage.[3]

Built by removing the second quarter at each iteration. Nowhere dense and not a countable set.   (golden ratio).

  0.69897 Real numbers with even digits   Similar to a Cantor set.[1]
  0.88137 Spectrum of Fibonacci Hamiltonian The study of the spectrum of the Fibonacci Hamiltonian proves upper and lower bounds for its fractal dimension in the large coupling regime. These bounds show that the spectrum converges to an explicit constant.[4]
  0<D<1 Generalized Cantor set   Built by removing at the  th iteration the central interval of length   from each remaining segment (of length  ). At   one obtains the usual Cantor set. Varying   between 0 and 1 yields any fractal dimension  .[5]
  1 Smith–Volterra–Cantor set   Built by removing a central interval of length   of each remaining interval at the nth iteration. Nowhere dense but has a Lebesgue measure of ½.
  1 Takagi or Blancmange curve   Defined on the unit interval by  , where   is the sawtooth function. Special case of the Takahi-Landsberg curve:   with  . The Hausdorff dimension equals   for  in . (Hunt cited by Mandelbrot[6]).
Calculated 1.0812 Julia set z² + 1/4   Julia set for c = 1/4.[7]
Solution s of   1.0933 Boundary of the Rauzy fractal   Fractal representation introduced by G.Rauzy of the dynamics associated to the Tribonacci morphism:  ,   and  .[8][9]   is one of the conjugated roots of  .
  1.12915 contour of the Gosper island   Term used by Mandelbrot (1977).[10] The Gosper island is the limit of the Gosper curve.
Measured (box counting) 1.2 Dendrite Julia set   Julia set for parameters: Real = 0 and Imaginary = 1.
  1.2083 Fibonacci word fractal 60°   Build from the Fibonacci word. See also the standard Fibonacci word fractal.

  (golden ratio).

  1.2108 Boundary of the tame twindragon   One of the six 2-rep-tiles in the plane (can be tiled by two copies of itself, of equal size).[11][12]
1.26 Hénon map   The canonical Hénon map (with parameters a = 1.4 and b = 0.3) has Hausdorff dimension 1.261 ± 0.003. Different parameters yield different dimension values.
  1.2619 Koch curve   3 von Koch curves form the Koch snowflake or the anti-snowflake.
  1.2619 boundary of Terdragon curve   L-system: same as dragon curve with angle = 30°. The Fudgeflake is based on 3 initial segments placed in a triangle.
  1.2619 2D Cantor dust   Cantor set in 2 dimensions.
  1.2619 2D L-system branch   L-Systems branching pattern having 4 new pieces scaled by 1/3. Generating the pattern using statistical instead of exact self-similarity yields the same fractal dimension.
Calculated 1.2683 Julia setz2 − 1   Julia set for c = −1.[13]
1.3057 Apollonian gasket   Starting with 3 tangent circles, repeatedly packing new circles into the complementary interstices. Also the limit set generated by reflections in 4 mutually tangent circles. See[14]
1.328 5circles inversion fractal   The limit set generated by iterated inversions with respect to 5 mutually tangent circles (in red). Also an Apollonian packing. See[15]
Calculated 1.3934 Douady rabbit   Julia set for c = −0,123 + 0.745i.[16]
  1.4649 Vicsek fractal   Built by exchanging iteratively each square by a cross of 5 squares.
  1.4649 Quadratic von Koch curve (type 1)   One can recognize the pattern of the Vicsek fractal (above).
  1.49 Quadric cross  
  (conjectured exact) 1.5000 aWeierstrass function:     The Hausdorff dimension of the Weierstrass function   defined by   with   and   has upper bound  . It is believed to be the exact value. The same result can be established when, instead of the sine function, we use other periodic functions, like cosine.[1]
  1.5000 Quadratic von Koch curve (type 2)   Also called "Minkowski sausage".
  1.5236 Boundary of the Dragon curve   cf. Chang & Zhang.[17][18]
  1.5236 Boundary of the twindragon curve   Can be built with two dragon curves. One of the six 2-rep-tiles in the plane (can be tiled by two copies of itself, of equal size).[11]
  1.5849 3-branches tree    Each branch carries 3 branches (here 90° and 60°). The fractal dimension of the entire tree is the fractal dimension of the terminal branches. NB: the 2-branches tree has a fractal dimension of only 1.
  1.5849 Sierpinski triangle   Also the triangle of Pascal modulo 2.
  1.5849 Sierpiński arrowhead curve   Same limit as the triangle (above) but built with a one-dimensional curve.
  1.5849 Boundary of the T-Square fractal   The dimension of the fractal itself (not the boundary) is  [19]
  1.61803 a golden dragon   Built from two similarities of ratios   and  , with  . Its dimension equals   because  . With   (Golden number).
  1.6309 Pascal triangle modulo 3   For a triangle modulo k, if k is prime, the fractal dimension is   (cf. Stephen Wolfram[20]).
  1.6309 Sierpinski Hexagon   Built in the manner of the Sierpinski carpet, on an hexagonal grid, with 6 similitudes of ratio 1/3. The Koch snowflake is present at all scales.
  1.6379 Fibonacci word fractal   Fractal based on the Fibonacci word (or Rabbit sequence) Sloane A005614. Illustration : Fractal curve after 23 steps (F23 = 28657 segments).[21]   (golden ratio).
Solution of   1.6402 Attractor of IFS with 3 similarities of ratios 1/3, 1/2 and 2/3   Generalization : Providing the open set condition holds, the attractor of an iterated function system consisting of   similarities of ratios  , has Hausdorff dimension  , solution of the equation coinciding with the iteration function of the Euclidean contraction factor:  .[1]
  1.6826 Pascal triangle modulo 5   For a triangle modulo k, if k is prime, the fractal dimension is   (cf. Stephen Wolfram[20]).
Measured (box-counting) 1.7 Ikeda map attractor   For parameters a=1, b=0.9, k=0.4 and p=6 in the Ikeda map  . It derives from a model of the plane-wave interactivity field in an optical ring laser. Different parameters yield different values.[22]
  1.7 50 segment quadric fractal   Built with ImageJ[23]
  1.7227 Pinwheel fractal   Built with Conway's Pinwheel tile.
  1.7712 Hexaflake   Built by exchanging iteratively each hexagon by a flake of 7 hexagons. Its boundary is the von Koch flake and contains an infinity of Koch snowflakes (black or white).
  1.7848 Von Koch curve 85°   Generalizing the von Koch curve with an angle a chosen between 0 and 90°. The fractal dimension is then  .
  1.8272 A self-affine fractal set   Build iteratively from a   array on a square, with  . Its Hausdorff dimension equals  [1] with   and   is the number of elements in the   column. The box-counting dimension yields a different formula, therefore, a different value. Unlike self-similar sets, the Hausdorff dimension of self-affine sets depends on the position of the iterated elements and there is no formula, so far, for the general case.
  1.8617 Pentaflake   Built by exchanging iteratively each pentagon by a flake of 6 pentagons.

  (golden ratio).

solution of   1.8687 Monkeys tree   This curve appeared in Benoit Mandelbrot's "Fractal geometry of Nature" (1983). It is based on 6 similarities of ratio   and 5 similarities of ratio  .[24]
  1.8928 Sierpinski carpet   Each face of the Menger sponge is a Sierpinski carpet, as is the bottom surface of the 3D quadratic Koch surface (type 1).
  1.8928 3D Cantor dust   Cantor set in 3 dimensions.
  1.8928 Cartesian product of the von Koch curve and the Cantor set   Generalization : Let F×G be the cartesian product of two fractals sets F and G. Then  .[1] See also the 2D Cantor dust and the Cantor cube.
Estimated 1.9340 Boundary of the Lévy C curve   Estimated by Duvall and Keesling (1999). The curve itself has a fractal dimension of 2.
1.974 Penrose tiling   See Ramachandrarao, Sinha & Sanyal.[25]
  2 Boundary of the Mandelbrot set   The boundary and the set itself have the same dimension.[26]
  2 Julia set   For determined values of c (including c belonging to the boundary of the Mandelbrot set), the Julia set has a dimension of 2.[27]
  2 Sierpiński curve   Every Peano curve filling the plane has a Hausdorff dimension of 2.
  2 Hilbert curve  
  2 Peano curve   And a family of curves built in a similar way, such as the Wunderlich curves.
  2 Moore curve   Can be extended in 3 dimensions.
2 Lebesgue curve or z-order curve   Unlike the previous ones this space-filling curve is differentiable almost everywhere. Another type can be defined in 2D. Like the Hilbert Curve it can be extended in 3D.[28]
  2 Dragon curve   And its boundary has a fractal dimension of 1.5236270862.[29]
2 Terdragon curve   L-system: F → F + F – F, angle = 120°.
  2 Gosper curve   Its boundary is the Gosper island.
Solution of   2 Curve filling the Koch snowflake   Proposed by Mandelbrot in 1982,[30] it fills the Koch snowflake. It is based on 7 similarities of ratio 1/3 and 6 similarities of ratio  .
  2 Sierpiński tetrahedron   Each tetrahedron is replaced by 4 tetrahedra.
  2 H-fractal   Also the Mandelbrot tree which has a similar pattern.
  2 Pythagoras tree (fractal)   Every square generates two squares with a reduction ratio of sqrt(2)/2.
  2 2D Greek cross fractal   Each segment is replaced by a cross formed by 4 segments.
Measured 2.01 ±0.01 Rössler attractor   The fractal dimension of the Rössler attractor is slightly above 2. For a=0.1, b=0.1 and c=14 it has been estimated between 2.01 and 2.02.[31]
Measured 2.06 ±0.01 Lorenz attractor   For parameters v=40, =16 and b=4 . See McGuinness (1983)[32]
  2.3219 Fractal pyramid   Each square pyramid is replaced by 5 half-size square pyramids. (Different from the Sierpinski tetrahedron, which replaces each triangular pyramid with 4 half-size triangular pyramids).
  2.3296 Dodecahedron fractal   Each dodecahedron is replaced by 20 dodecahedra.

  (golden ratio).

  2.3347 3D quadratic Koch surface (type 1)   Extension in 3D of the quadratic Koch curve (type 1). The illustration shows the second iteration.
2.4739 Apollonian sphere packing   The interstice left by the Apollonian spheres. Apollonian gasket in 3D. Dimension calculated by M. Borkovec, W. De Paris, and R. Peikert.[33]
  2.50 3D quadratic Koch surface (type 2)   Extension in 3D of the quadratic Koch curve (type 2). The illustration shows the second iteration.
  2.5237 Cantor tesseract no image available Cantor set in 4 dimensions. Generalization: in a space of dimension n, the Cantor set has a Hausdorff dimension of  .
  2.529 Jerusalem cube   The iteration n is built with 8 cubes of iteration n-1 (at the corners) and 12 cubes of iteration n-2 (linking the corners). The contraction ratio is  .
  2.5819 Icosahedron fractal   Each icosahedron is replaced by 12 icosahedra.   (golden ratio).
  2.5849 3D Greek cross fractal   Each segment is replaced by a cross formed by 6 segments.
  2.5849 Octahedron fractal   Each octahedron is replaced by 6 octahedra.
  2.5849 von Koch surface   Each equilateral triangular face is cut into 4 equal triangles.

Using the central triangle as the base, form a tetrahedron. Replace the triangular base with the tetrahedral "tent".

  2.7268 Menger sponge   And its surface has a fractal dimension of  , which is the same as that by volume.
  3 3D Hilbert curve   A Hilbert curve extended to 3 dimensions.
  3 3D Lebesgue curve   A Lebesgue curve extended to 3 dimensions.
  3 3D Moore curve   A Moore curve extended to 3 dimensions.
  3 3D H-fractal   A H-fractal extended to 3 dimensions.[34]
  (to be confirmed) 3 (to be confirmed) Mandelbulb   Extension of the Mandelbrot set (power 8) in 3 dimensions[35][unreliable source?]

Random and natural fractals

Hausdorff dimension
(exact value)
Hausdorff dimension
(approx.)
Name Illustration Remarks
1/2 0.5 Zeros of a Wiener process   The zeros of a Wiener process (Brownian motion) are a nowhere dense setofLebesgue measure 0 with a fractal structure.[1][36]
Solution of   where   and   0.7499 a random Cantor set with 50% - 30%   Generalization : At each iteration, the length of the left interval is defined with a random variable  , a variable percentage of the length of the original interval. Same for the right interval, with a random variable  . Its Hausdorff Dimension   satisfies :  . (  is the expected valueof ).[1]
Solution of   1.144... von Koch curve with random interval   The length of the middle interval is a random variable with uniform distribution on the interval (0,1/3).[1]
Measured 1.22±0.02 Coastline of Ireland   Values for the fractal dimension of the entire coast of Ireland were determined by McCartney, Abernethy and Gault[37] at the University of Ulster and Theoretical Physics students at Trinity College, Dublin, under the supervision of S. Hutzler.[38]

Note that there are marked differences between Ireland's ragged west coast (fractal dimension of about 1.26) and the much smoother east coast (fractal dimension 1.10)[38]

Measured 1.25 Coastline of Great Britain   Fractal dimension of the west coast of Great Britain, as measured by Lewis Fry Richardson and cited by Benoît Mandelbrot.[39]
  1.2619 von Koch curve with random orientation   One introduces here an element of randomness which does not affect the dimension, by choosing, at each iteration, to place the equilateral triangle above or below the curve.[1]
  1.333 Boundary of Brownian motion   (cf. Mandelbrot, Lawler, Schramm, Werner).[40]
  1.333 2D polymer Similar to the brownian motion in 2D with non self-intersection.[41]
  1.333 Percolation front in 2D, Corrosion front in 2D   Fractal dimension of the percolation-by-invasion front (accessible perimeter), at the percolation threshold (59.3%). It's also the fractal dimension of a stopped corrosion front.[41]
1.40 Clusters of clusters 2D When limited by diffusion, clusters combine progressively to a unique cluster of dimension 1.4.[41]
  1.5 Graph of a regular Brownian function (Wiener process)   Graph of a function f such that, for any two positive reals x and x+h, the difference of their images   has the centered gaussian distribution with variance = h. Generalization : The fractional Brownian motion of index   follows the same definition but with a variance  , in that case its Hausdorff dimension = .[1]
Measured 1.52 Coastline of Norway   See J. Feder.[42]
Measured 1.55 Random walk with no self-intersection   Self-avoiding random walk in a square lattice, with a « go-back » routine for avoiding dead ends.
  1.66 3D polymer Similar to the brownian motion in a cubic lattice, but without self-intersection.[41]
1.70 2D DLA Cluster   In 2 dimensions, clusters formed by diffusion-limited aggregation, have a fractal dimension of around 1.70.[41]
  1.7381 Fractal percolation with 75% probability   The fractal percolation model is constructed by the progressive replacement of each square by a 3x3 grid in which is placed a random collection of sub-squares, each sub-square being retained with probability p. The "almost sure" Hausdorff dimension equals  .[1]
7/4 1.75 2D percolation cluster hull   The hull or boundary of a percolation cluster. Can also be generated by a hull-generating walk,[43] or by Schramm-Loewner Evolution.
  1.8958 2D percolation cluster   In a square lattice, under the site percolation threshold (59.3%) the percolation-by-invasion cluster has a fractal dimension of 91/48.[41][44] Beyond that threshold, the cluster is infinite and 91/48 becomes the fractal dimension of the « clearings ».
  2 Brownian motion   Or random walk. The Hausdorff dimensions equals 2 in 2D, in 3D and in all greater dimensions (K.Falconer "The geometry of fractal sets").
Measured Around 2 Distribution of galaxy clusters   From the 2005 results of the Sloan Digital Sky Survey.[45]
  2.33 Cauliflower   Every branch carries around 13 branches 3 times smaller.
2.5 Balls of crumpled paper   When crumpling sheets of different sizes but made of the same type of paper and with the same aspect ratio (for example, different sizes in the ISO 216 A series), then the diameter of the balls so obtained elevated to a non-integer exponent between 2 and 3 will be approximately proportional to the area of the sheets from which the balls have been made.[46] Creases will form at all size scales (see Universality (dynamical systems)).
2.50 3D DLA Cluster   In 3 dimensions, clusters formed by diffusion-limited aggregation, have a fractal dimension of around 2.50.[41]
2.50 Lichtenberg figure   Their appearance and growth appear to be related to the process of diffusion-limited aggregation or DLA.[41]
  2.5 regular Brownian surface   A function  , gives the height of a point   such that, for two given positive increments   and  , then   has a centered Gaussian distribution with variance =  . Generalization : The fractional Brownian surface of index   follows the same definition but with a variance =  , in that case its Hausdorff dimension =  .[1]
Measured 2.52 3D percolation cluster   In a cubic lattice, at the site percolation threshold (31.1%), the 3D percolation-by-invasion cluster has a fractal dimension of around 2.52.[44] Beyond that threshold, the cluster is infinite.
Measured 2.66 Broccoli   [47]
2.79 Surface of human brain   [48]
2.97 Lung surface   The alveoli of a lung form a fractal surface close to 3.[41]
Calculated   Multiplicative cascade   This is an example of a multifractal distribution. However by choosing its parameters in a particular way we can force the distribution to become a monofractal.[49]

See also

Notes and references

  1. ^ a b c d e f g h i j k l m Falconer, Kenneth (1990 & 2003). Fractal Geometry: Mathematical Foundations and Applications. John Wiley & Sons, Ltd. xxv. ISBN 0-470-84862-6. {{cite book}}: Check date values in: |year= (help); Unknown parameter |nopp= ignored (|no-pp= suggested) (help)
  • ^ Fractal dimension of the Feigenbaum attractor
  • ^ Tsang, K. Y. (1986). "Dimensionality of Strange Attractors Determined Analytically". Phys. Rev. Lett. 57 (12): 1390–1393. doi:10.1103/PhysRevLett.57.1390. PMID 10033437.
  • ^ Fractal dimension of the spectrum of the Fibonacci Hamiltonian
  • ^ The scattering from generalized Cantor fractals
  • ^ Mandelbrot, Benoit. Gaussian self-affinity and Fractals. ISBN 0-387-98993-5.
  • ^ fractal dimension of the Julia set for c = 1/4
  • ^ Boundary of the Rauzy fractal
  • ^ Lothaire, M. (2005), Applied combinatorics on words, Encyclopedia of Mathematics and its Applications, vol. 105, Cambridge University Press, p. 525, ISBN 978-0-521-84802-2; 978-0-521-84802-2, MR 2165687, Zbl 1133.68067 {{citation}}: Check |isbn= value: invalid character (help)
  • ^ Gosper island on Mathworld
  • ^ a b On 2-reptiles in the plane, Ngai, 1999
  • ^ Recurrent construction of the boundary of the dragon curve (for n=2, D=1)
  • ^ fractal dimension of the z²-1 Julia set
  • ^ fractal dimension of the apollonian gasket
  • ^ fractal dimension of the 5 circles inversion fractal
  • ^ fractal dimension of the Douady rabbit
  • ^ Fractal dimension of the boundary of the dragon fractal
  • ^ Recurrent construction of the boundary of the dragon curve (for n=2, D=2)
  • ^ T-Square (fractal)
  • ^ a b Fractal dimension of the Pascal triangle modulo k
  • ^ The Fibonacci word fractal
  • ^ Estimating Fractal dimension
  • ^ Fractal Generator for ImageJ.
  • ^ Monkeys tree fractal curve
  • ^ Fractal dimension of a Penrose tiling
  • ^ Fractal dimension of the boundary of the Mandelbrot set
  • ^ Fractal dimension of certain Julia sets
  • ^ Lebesgue curve variants
  • ^ Complex base numeral systems
  • ^ "Penser les mathématiques", Seuil ISBN 2-02-006061-2 (1982)
  • ^ Fractals and the Rössler attractor
  • ^ The fractal dimension of the Lorenz attractor, Mc Guinness (1983)
  • ^ Fractal dimension of the apollonian sphere packing
  • ^ B. Hou, H. Xie, W. Wen, and P. Sheng (2008). "Three-dimensional metallic fractals and their photonic crystal characteristics". Phys. Rev. B 77, 125113. {{cite journal}}: Cite journal requires |journal= (help); Italic or bold markup not allowed in: |publisher= (help)CS1 maint: multiple names: authors list (link)
  • ^ Hausdorff dimension of the Mandelbulb
  • ^ Peter Mörters, Yuval Peres, Oded Schramm, "Brownian Motion", Cambridge University Press, 2010
  • ^ McCartney M., Abernethy G., and Gault L. (2010). The Divider Dimension of the Irish Coast. Irish Geography, 43, 277-284.
  • ^ a b Hutzler, S. (2013). Fractal Ireland. Science Spin, 58, 19-20.
  • ^ How long is the coast of Britain? Statistical self-similarity and fractional dimension, B. Mandelbrot
  • ^ Fractal dimension of the brownian motion boundary
  • ^ a b c d e f g h i Bernard Sapoval "Universalités et fractales", Flammarion-Champs (2001), ISBN=2-08-081466-4
  • ^ Feder, J., "Fractals,", Plenum Press, New York, (1988).
  • ^ Hull-generating walks
  • ^ a b "Applications of percolation" theory by Muhammad Sahimi (1994)
  • ^ Basic properties of galaxy clustering in the light of recent results from the Sloan Digital Sky Survey
  • ^ "Power Law Relations". Yale. Retrieved 29 July 2010Template:Inconsistent citations {{cite journal}}: Cite journal requires |journal= (help)CS1 maint: postscript (link)
  • ^ Fractal dimension of the broccoli
  • ^ Fractal dimension of the surface of the human brain
  • ^ [Meakin (1987)]
  • Further reading


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