Fractals/Iterations in the complex plane/def cqp

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Definitions


Contents

Address[edit]

Internal[edit]

Internal addresses describe the combinatorial structure of the Mandelbrot set.

angled[edit]

Angled internal address is an extension of internal address

Angle[edit]

Types of angle[edit]

external angle internal angle plain angle
parameter plane  arg(\Phi_M(c))  \,  arg(\rho_n(c)) \,  arg(c) \,
dynamic plane  arg(\Phi_c(z)) \,  arg(z) \,

where :

external[edit]

The external angle is a angle of point of set's exterior. It is the same on all points on the external ray

internal[edit]

The internal angle is an angle of point of component's interior

  • it is a rational number and proper fraction measured in turns
  • it is the same for all point on the internal ray
  • in a contact point ( root point ) it agrees with the rotation number
  • root point has internal angle 0


\alpha = \frac{p}{q} \in \mathbb{Q}

plain[edit]

The plain angle is an agle of complex point = it's argument [1]

Units[edit]

  • turns
  • degrees
  • radians

Number types[edit]

Angle ( for example external angle in turns ) can be used in different number types

Examples :

the external arguments of the rays landing at z = −0.15255 + 1.03294i are :[2]

(\theta^- _{20} , \theta^+_{20} ) = (0.\overline{00110011001100110100}, 0.\overline{00110011001101000011})

where :

\theta^- _{20}  = 0.\overline{00110011001100110100}_2 = 0.\overline{20000095367522590181913549340772}_{10} = \frac{209716}{1048575} = \frac{209716}{2^{20}-1}

Coordinate[edit]

  • Fatou coordinate for every repelling and attracting petal ( linearization of function near parabolic fixed point )

Curves[edit]

Circle[edit]

Inner circle[edit]

Unit circle[edit]

Unit circle \partial D\, is a boundary of unit disk[3]

\partial D = \left\{ w: abs(w)=1  \right \}

where coordinates of w\, point of unit circle in exponential form are :

w = e^{i*t}\,


Critical curves[edit]

Diagrams of critical polynomials are called critical curves.[4]

These curves create skeleton of bifurcation diagram.[5] (the dark lines[6])

Isocurves[edit]

Equipotential lines[edit]

Jordan curve[edit]

Illustration of the Jordan curve theorem. The Jordan curve (drawn in black) divides the plane into an "inside" region (light blue) and an "outside" region (pink).

Jordan curve = a simple closed curve that divides the plane into an "interior" region bounded by the curve and an "exterior" region containing all of the nearby and far away exterior points[7]

Lamination[edit]

Lamination of the unit disk is a closed collection of chords in the unit disc, which can intersect only in an endpoint of each on the boundary circle[8][9]

It is a model of Mandelbrot or Julia set.


A lamination, L, is a union of leaves and the unit circle which satisfies :[10]

  • leaves do not cross (although they may share endpoints) and
  • L is a closed set.

Leaf[edit]

Chords = leaves = arcs

A leaf on the unit disc is a path connecting two points on the unit circle. [11]


Ray[edit]

External ray[edit]

Internal ray[edit]

Dynamic internal ( blue segment) and external ( red ray) rays

Internal rays are :

  • dynamic ( on dynamic plane , inside filled Julia set )
  • parameter ( on parameter plane , inside Mandelbrot set )

Spider[edit]

A spider S is a collection of disjoint simple curves called legs [12]( extended rays = external + internal ray) in the complex plane connecting each of the post-critical points to infnity [13] See spider algorithm for more.

Derivative[edit]

Derivative of Iterated function (map)

Derivative with respect to c[edit]

On parameter plane :

  • c is a variable
  • z_0 = 0 is constant
\frac{d}{dc} f^{(p)} _c (z_0) = z'_p \,

This derivative can be found by iteration starting with


z_0 = 0 \,
z'_0 = 1 \,


and then

z_p = z_{p-1}^2 + c \,
z'_p = 2 \cdot z_{p-1}\cdot z'_{p-1} + 1 \,

This can be verified by using the chain rule for the derivative.

  • Maxima CAS function :


dcfn(p, z, c) :=
  if p=0 then 1
  else 2*fn(p-1,z,c)*dcfn(p-1, z, c)+1;


Example values :

z_0 = 0 \qquad\qquad z'_0 = 1 \,
z_1 = c \qquad\qquad z'_1 =  1 \,
z_2 = c^2+c \qquad z'_2 = 2c+1 \,


Derivative with respect to z[edit]

z'_n\, is first derivative with respect to c.


This derivative can be found by iteration starting with

z'_0 = 1 \,

and then :

z'_n= 2*z_{n-1}*z'_{n-1}\,


Iteration[edit]

Iteration

Magnitude[edit]

magnitude of the point = it's distance from the origin

Multiplier[edit]

Multiplier of periodic z-point : [14]

Math notation :

\lambda_c(z) = \frac{df_c^{(p)}(z)}{dz}\,

Maxima CAS function for computing multiplier of periodic cycle :

m(p):=diff(fn(p,z,c),z,1);

where p is a period. It takes period as an input, not z point.

period f^p(z) \, \lambda_c(z) \,
1 z^2 + c \, 2z \,
2 z^4 + 2cz^2 + c^2 + c 4z^3 + 4cz
3 z^8 + 4cz^6 + 6c^2z^4 + 2cz^4 + 4c^3z^2 + 4c^2z^2 + c^4 + 2c^3 + c^2 + c 8z^7 + 24cz^5 + 24c^2z^3 + 8cz^3 + 8c^3z + 8c^2z


It is used to :

  • compute stability index of periodic orbit ( periodic point) = |\lambda| = r ( where r is a n internal radius
  • multiplier map

Map[edit]

  • Iterated function = map[15]
  • an evolution function[16] of the discrete nonlinear dynamical system[17]
z_{n+1} = f_c(z_n)  \,

is called map f_c :

f_c : z \to z^2 + c. \,


Complex quadratic map[edit]

Forms[edit]

c form : z^2+c[edit]

quadratic map[18]

  • math notation : f_c(z)=z^2+c\,
  • Maxima CAS function :
f(z,c):=z*z+c;
(%i1) z:zx+zy*%i;
(%o1) %i*zy+zx
(%i2) c:cx+cy*%i;
(%o2) %i*cy+cx
(%i3) f:z^2+c;
(%o3) (%i*zy+zx)^2+%i*cy+cx
(%i4) realpart(f);
(%o4) -zy^2+zx^2+cx
(%i5) imagpart(f);
(%o5) 2*zx*zy+cy

Iterated quadratic map

  • math notation


 \ f^{(0)} _c (z) =   z = z_0
 \ f^{(1)} _c (z) =   f_c(z) = z_1

...

 \ f^{(p)} _c (z) =   f_c(f^{(p-1)} _c (z))

or with subscripts :

 \ z_p =  f^{(p)} _c (z_0)
  • Maxima CAS function :
fn(p, z, c) :=
  if p=0 then z
  elseif p=1 then f(z,c)
  else f(fn(p-1, z, c),c);
zp:fn(p, z, c);

lambda form :  z^2+\lambda z[edit]

More description Maxima CAS code ( here m not lambda is used )  :

(%i2) z:zx+zy*%i;
(%o2) %i*zy+zx
(%i3) m:mx+my*%i;
(%o3) %i*my+mx
(%i4) f:m*z+z^2;
(%o4) (%i*zy+zx)^2+(%i*my+mx)*(%i*zy+zx)
(%i5) realpart(f);
(%o5) -zy^2-my*zy+zx^2+mx*zx
(%i6) imagpart(f);
(%o6) 2*zx*zy+mx*zy+my*zx

Switching between forms[edit]

Start from :

  • internal angle \theta = \frac {p}{q}
  • internal radius r

Multiplier of fixed point :

\lambda = r e^{2 \pi \theta i}


When one wants change from lambda to c :[19]

c = c(\lambda) = \frac {\lambda}{2} \left(1 - \frac {\lambda}{2}\right) = \frac {\lambda}{2} - \frac {\lambda^2}{4}

or from c to lambda :

\lambda = \lambda(c) = 1 \pm  \sqrt{1- 4 c}

Example values :

\theta r c fixed point alfa z_c \lambda fixed point z_{\lambda}
1/1 1.0 0.25 0.5 1.0 0
1/2 1.0 -0.75 -0.5 -1.0 0
1/3 1.0 0.64951905283833*i-0.125 0.43301270189222*i-0.25 0.86602540378444*i-0.5 0
1/4 1.0 0.5*i+0.25 0.5*i i 0
1/5 1.0 0.32858194507446*i+0.35676274578121 0.47552825814758*i+0.15450849718747 0.95105651629515*i+0.30901699437495 0
1/6 1.0 0.21650635094611*i+0.375 0.43301270189222*i+0.25 0.86602540378444*i+0.5 0
1/7 1.0 0.14718376318856*i+0.36737513441845 0.39091574123401*i+0.31174490092937 0.78183148246803*i+0.62348980185873 0
1/8 1.0 0.10355339059327*i+0.35355339059327 0.35355339059327*i+0.35355339059327 0.70710678118655*i+0.70710678118655 0
1/9 1.0 0.075191866590218*i+0.33961017714276 0.32139380484327*i+0.38302222155949 0.64278760968654*i+0.76604444311898 0
1/10 1.0 0.056128497072448*i+0.32725424859374 0.29389262614624*i+0.40450849718747 0.58778525229247*i+0.80901699437495


One can easily compute parameter c as a point c inside main cardioid of Mandelbrot set :

 c = c_x + c_y*i

of period 1 hyperbolic component ( main cardioid) for given internal angle ( rotation number) t using this c / cpp code by Wolf Jung[20]

double InternalAngleInTurns;
double InternalRadius;
double t = InternalAngleInTurns *2*M_PI; // from turns to radians
double R2 = InternalRadius * InternalRadius;
double Cx, Cy; /* C = Cx+Cy*i */
// main cardioid
Cx = (cos(t)*InternalRadius)/2-(cos(2*t)*R2)/4; 
Cy = (sin(t)*InternalRadius)/2-(sin(2*t)*R2)/4; 

or this Maxima CAS code :

 
/* conformal map  from circle to cardioid ( boundary
 of period 1 component of Mandelbrot set */
F(w):=w/2-w*w/4;

/* 
circle D={w:abs(w)=1 } where w=l(t,r) 
t is angle in turns ; 1 turn = 360 degree = 2*Pi radians 
r is a radius 
*/
ToCircle(t,r):=r*%e^(%i*t*2*%pi);

GiveC(angle,radius):=
(
 [w],
 /* point of  unit circle   w:l(internalAngle,internalRadius); */
 w:ToCircle(angle,radius),  /* point of circle */
 float(rectform(F(w)))    /* point on boundary of period 1 component of Mandelbrot set */
)$

compile(all)$

/* ---------- global constants & var ---------------------------*/
Numerator :1;
DenominatorMax :10;
InternalRadius:1;

/* --------- main -------------- */
for Denominator:1 thru DenominatorMax step 1 do
(
 InternalAngle: Numerator/Denominator,
 c: GiveC(InternalAngle,InternalRadius),
 display(Denominator),
 display(c),
  /* compute fixed point */
 alfa:float(rectform((1-sqrt(1-4*c))/2)), /* alfa fixed point */
 display(alfa)
 )$


Doubling map[edit]

definition [21]

  • Maxima CAS function using numerator and denominator as an input
doubling_map(n,d):=mod(2*n,d)/d $

or using rational number as an input

DoublingMap(r):=
  block([d,n],
        n:ratnumer(r),
        d:ratdenom(r),
        mod(2*n,d)/d)$


  • Common Lisp function
(defun doubling-map (ratio-angle)
" period doubling map =  The dyadic transformation (also known as the dyadic map, 
 bit shift map, 2x mod 1 map, Bernoulli map, doubling map or sawtooth map "
(let* ((n (numerator ratio-angle))
       (d (denominator ratio-angle)))
  (setq n  (mod (* n 2) d)) ; (2 * n) modulo d
  (/ n d))) ; result  = n/d
  • Haskell function[22]
-- by Claude Heiland-Allen
-- type Q = Rational
 double :: Q -> Q
 double p
   | q >= 1 = q - 1
   | otherwise = q
   where q = 2 * p
  • C++
//  mndcombi.cpp  by Wolf Jung (C) 2010. 
//   http://mndynamics.com/indexp.html 
// n is a numerator
// d is a denominator
// f = n/d is a rational fraction ( angle in turns )
// twice is doubling map = (2*f) mod 1
// n and d are changed ( Arguments passed to function by reference)
 
void twice(unsigned long long int &n, unsigned long long int &d)
{  if (n >= d) return;
   if (!(d & 1)) { d >>= 1; if (n >= d) n -= d; return; }
   unsigned long long int large = 1LL; 
   large <<= 63; //avoid overflow:
   if (n < large) { n <<= 1; if (n >= d) n -= d; return; }
   n -= large; 
   n <<= 1; 
   large -= (d - large); 
   n += large;
}

Inverse function of doubling map[edit]

Every angle α ∈ R/Z measured in turns has :

In Maxima CAS :

InvDoublingMap(r):= [r/2, (r+1)/2];

Note that difference between these 2 preimages

\frac{\alpha}{2} - \frac{\alpha +1}{2} = \frac{1}{2}

is half a turn = 180 degrees = Pi radians.

Images and preimages under doubling map d
\alpha d^1(\alpha) d^{-1}(\alpha)
\frac{1}{2} \frac{1}{1} \left \{ \frac{1}{4} , \frac{3}{4} \right \}
\frac{1}{3} \frac{2}{3} \left \{ \frac{1}{6} , \frac{4}{6} \right \}
\frac{1}{4} \frac{1}{2} \left \{ \frac{1}{8} , \frac{5}{8} \right \}
\frac{1}{5} \frac{2}{5} \left \{ \frac{1}{10} , \frac{6}{10} \right \}
\frac{1}{6} \frac{1}{3} \left \{ \frac{1}{12} , \frac{7}{12} \right \}
\frac{1}{7} \frac{2}{7} \left \{ \frac{1}{14} , \frac{4}{7} \right \}

First return map[edit]

definition [24]

"In contrast to a phase portrait, the return map is a discrete description of the underlying dynamics. .... A return map (plot) is generated by plotting one return value of the time series against the previous one "[25]

"If x is a periodic point of period p for f and U is a neighborhood of x, the composition f^{\circ p}\, maps U to another neighborhood V of x. This locally defined map is the return map for x." ( W P Thurston : On the geometry and dynamics of Iterated rational maps)

Multiplier map[edit]

Multiplier map  \lambda gives an explicit uniformization of hyperbolic component \Eta by the unit disk \mathbb{D}  :

 \lambda : \Eta \to \mathbb{D}

Multiplier map is a conformal isomorphism.[26]

Number[edit]

Rotation number[edit]

The rotation number[27][28][29] of the disk ( component) attached to the main cardioid of the Mandelbrot set is a proper, positive rational number p/q in lowest terms where :

  • q is a period of attached disk ( child period ) = the period of the attractive cycles of the Julia sets in the attached disk
  • p descibes fc action on the cycle : fc turns clockwise around z0 jumping, in each iteration, p points of the cycle [30]

Features :

  • in a contact point ( root point ) it agrees with the internal angle
  • the rotation numbers are ordered clockwise along the boundary of the componant
  • " For parameters c in the p/q-limb, the filled Julia set Kc has q components at the fixed point αc . These are permuted cyclically by the quadratic polynomial fc(z), going p steps counterclockwise " Wolf Jung

Orbit[edit]

Backward[edit]

Critical[edit]

Forward orbit[31] of a critical point[32][33] is called a critical orbit. Critical orbits are very important because every attracting periodic orbit[34] attracts a critical point, so studying the critical orbits helps us understand the dynamics in the Fatou set.[35][36]

z_0 = z_{cr} = 0\,

z_1 = f_c(z_0) = c\,

z_2 = f_c(z_1) = c^2 +c\,

z_3 = f_c(z_2) = (c^2 + c)^2 + c\,

... \,

This orbit falls into an attracting periodic cycle.

Here are images of critical orbits

Forward[edit]

Inverse[edit]

Inverse = Backward

Parameter[edit]

Parameter ( point of parameter plane ) " is renormalizable if restriction of some of its iterate gives a polinomial-like map of the same or lower degree. " [37]

Period[edit]

The smallest positive integer value p for which this equality

 f^p(z_0) = z_0 

holds is the period of the orbit.[38]

 z_0 is a point of periodic orbit ( limit cycle ) \{z_0, \dots , z_{p-1} \}.


More is here

Plane[edit]

Planes [39]

Dynamic plane[edit]

  • z-plane for fc(z)= z^2 + c
  • z-plane for fm(z)= z^2 + m*z

Parameter plane[edit]

See :[40]

  • exponential plane ( map) [41][42]
  • flatten' the cardiod ( unroll ) [43][44] = "A region along the cardioid is continuously blown up and stretched out, so that the respective segment of the cardioid becomes a line segment. .." ( Figure 4.22 on pages 204-205 of The Science Of Fractal Images)[45]
  • transformations [46]


Points[edit]

Band-merging points[edit]

the band-merging points are Misiurewicz points[47]

Biaccessible point[edit]

If there exist two distinct external rays landing at point we say that it is a biaccessible point. [48]

Center[edit]

Center of hyperbolic component[edit]

A center of a hyperbolic component H is a parameter  c_0 \in H\, ( or point of parameter plane ) such that the corresponding periodic orbit has multiplier= 0." [49]

Center of Siegel Disc[edit]

Center of Siegel disc is a irrationally indifferent periodic point.

Mane's theorem :

"... appart from its center, a Siegel disk cannot contain any periodic point, critical point, nor any iterated preimage of a critical or periodic point. On the other hand it can contain an iterated image of a critical point." [50]

Critical point[edit]

A critical point[51] of f_c\, is a point  z_{cr} \, in the dynamical plane such that the derivative vanishes:

f_c'(z_{cr}) = 0. \,

Since

f_c'(z) = \frac{d}{dz}f_c(z) = 2z

implies

 z_{cr} = 0\,

we see that the only (finite) critical point of f_c \, is the point  z_{cr} = 0\,.

z_0 is an initial point for Mandelbrot set iteration.[52]

Cut point, ray and angle[edit]

The "neck" of this eight-like figure is a cut-point.
Cut points in the San Marco Basilica Julia set. Biaccessible points = landing points for 2 external rays

Cut point k of set S is a point for which set S-k is dissconected ( consist of 2 or more sets).[53] This name is used in a topology.

Examples :

  • root points of Mandelbrot set
  • Misiurewicz points of boundary of Mandelbrot set
  • cut points of Julia sets ( in case of Siegel disc critical point is a cut point )

These points are landing points of 2 or more external rays.

Point which is a landing point of 2 external rays is called biaccesible


Cut ray is a ray which converges to landing point of another ray. [54] Cut rays can be used to construct puzzles.

Cut angle is an angle of cut ray.

Feigenbaum Point[edit]

Self similarity in the Mandelbrot set shown by zooming in on a round feature while panning in the negative-x direction. The display center pans from (−1, 0) to (−1.31, 0) while the view magnifies from 0.5 × 0.5 to 0.12 × 0.12 to approximate the Feigenbaum ratio \delta.

The Feigenbaum Point[55] is a :

  • point c of parameter plane
  • is the limit of the period doubling cascade of bifurcations
  • an infinitely renormalizable parameter of bounded type
  • boundary point between chaotic ( -2 < c < MF ) and periodic region ( MF< c < 1/4)[56]

MF^{(n)} (\tfrac{p}{q}) = c

Generalized Feigenbaum points are :

  • the limit of the period-q cascade of bifurcations
  • landing points of parameter ray or rays with irrational angles

Examples :

  • MF^{(0)} = MF^{(1)} (\tfrac{1}{2}) = c = -1.401155
  • -.1528+1.0397i)

The Mandelbrot set is conjectured to be self- similar around generalized Feigenbaum points[57] when the magnification increases by 4.6692 (the Feigenbaum Constant) and period is doubled each time[58]

n Period = 2^n Bifurcation parameter = cn Ratio = \dfrac{c_{n-1}-c_{n-2}}{c_n-c_{n-1}}
1 2 -0.75 N/A
2 4 -1.25 N/A
3 8 -1.3680989 4.2337
4 16 -1.3940462 4.5515
5 32 -1.3996312 4.6458
6 64 -1.4008287 4.6639
7 128 -1.4010853 4.6682
8 256 -1.4011402 4.6689
9 512 -1.401151982029
10 1024 -1.401154502237
infinity -1.4011551890 ...

Bifurcation parameter is a root point of period = 2^n component. This series converges to the Feigenbaum point c = −1.401155

The ratio in the last column converges to the first Feigenbaum constant.

Misiurewicz point[edit]

Misiurewicz point[59]

Characteristic Misiurewicz pointof the chaotic band of the Mandelbrot set is :[60]

  • the most prominent and visible Misiurewicz point of a chaotic band
  • have the same period as the band
  • have the same period as the gene of the band

the Myrberg-Feigenbaum point[edit]

MF = the Myrberg-Feigenbaum point is the different name for the Feigenbaum Point.

Periodic point[edit]

Point z has period p under f if :

 z : \ f^{p} (z) =   z

Pinching points[edit]

"Pinching points are found as the common landing points of external rays, with exactly one ray landing between two consecutive branches. They are used to cut M or K into well-defined components, and to build topological models for these sets in a combinatorial way. " ( definition from Wolf Jung program Mandel )

See for examples :

  • period 2 = Mandel, demo 2 page 3.
  • period 3 = Mandel, demo 2 page 5 [61]

A post-critical point[edit]

A post-critical point is a point

 z = f(f(f( ... (z_{cr})))) 

where z_{cr} is a critical point. [62]


root point[edit]

The root point :

  • has a rotational number 0
  • it is a biaccesible point ( landing point of 2 external rays )

Polynomial[edit]

Critical polynomial[edit]

Q_n = f_c^n(z_{cr}) = f_c^n(0) \,

so

Q_1 = f_c^1(0) = c \,

Q_2 = f_c^2(0) = c^2 + c \,

Q_3 = f_c^3(0) = (c^2 + c)^2 + c \,

These polynomials are used for finding :

  • centers of period n Mandelbrot set components. Centers are roots of n-th critical polynomials centers = \{ c : f_c^n(z_{cr}) = 0 \}\, ( points where critical curve Qn croses x axis )
  • Misiurewicz points M_{n,k} = \{ c : f_c^k(z_{cr}) = f_c^{k+n}(z_{cr}) \}\,

Portrait[edit]

orbit portrait[edit]

types[edit]

There are two types of orbit portraits: primitive and satellite. [63]If v is the valence of an orbit portrait \mathcal P and r is the recurrent ray period, then these two types may be characterized as follows:

  • Primitive orbit portraits have r = 1 and v = 2. Every ray in the portrait is mapped to itself by f^n. Each A_j is a pair of angles, each in a distinct orbit of the doubling map. In this case, r_{\mathcal P} is the base point of a baby Mandelbrot set in parameter space.
  • Satellite ( non-primitive ) orbit portraits have r = v \ge 2. In this case, all of the angles make up a single orbit under the doubling map. Additionally, r_{\mathcal P} is the base point of a parabolic bifurcation in parameter space.

Processes[edit]

Contraction and dilatation[edit]

  • the contraction z → z/2
  • the dilatation z → 2z.

Implosion and explosion[edit]

Explosion (above) and implosion ( below)

Implosion is :

  • the process of sudden change of quality fuatures of the object, like collapsing (or being squeezed in)
  • the opposite of explosion

Example : parabolic implosion in complex dynamics, when filled Julia for complex quadratic polynomial set looses all its interior ( when c goes from 0 along internal ray 0 thru parabolic point c=1/4 and along extrnal ray 0 = when c goes from interior , crosses the bounday to the exterior of Mandelbrot set)


Explosion is a :

  • is a sudden change of quality fuatures of the object in an extreme manner,
  • the opposite of implosion

Example : in exponential dynamics when λ> 1/e , the Julia set of E_{\lambda}(z) = \lambda e^z is the entire plane.[64]

Radius[edit]

Conformal radius[edit]

Conformal radius of Siegel Disk [65][66]

Escape radius ( ER)[edit]

Escape radius ( ER ) or bailout value is a radius of circle target set used in bailout test

Minimal Escape Radius should be grater or equal to 2 :

 ER  =  max ( 2 , |c| )\,

Better estimation is :[67][68]

ER = \frac{1}{2} +\sqrt{\frac{1}{4} + |c| }


Inner radius[edit]

Inner radius of Siegel Disc

  • radius of inner circle, where inner circle with center at fixed point is the biggest circle inside Siegel Disc.
  • minimal distance between center of Siel Disc and critical orbit

Internal radius[edit]

Internal radius is a:

Sequences[edit]

A sequence is an ordered list of objects (or events).[69]

A series is the sum of the terms of a sequence of numbers.[70] Some times these names are not used as in above definitions.

The upper principal sequence of rotational number around the main cardioid of Mandelbrot set[71]

n rotation number = 1/n parameter c
2 1/2 -0.75
3 1/3 0.64951905283833*i-0.125
4 1/4 0.5*i+0.25
5 1/5 0.32858194507446*i+0.35676274578121
6 1/6 0.21650635094611*i+0.375
7 1/7 0.14718376318856*i+0.36737513441845
8 1/8 0.10355339059327*i+0.35355339059327
9 1/9 0.075191866590218*i+0.33961017714276
10 1/10 0.056128497072448*i+0.32725424859374

Set[edit]

Continuum[edit]

definition[72]

Component[edit]

Components of parameter plane[edit]

Hyperbolic component of Mandelbrot set[edit]

Boundaries of hyperbolic components of Mandelbrot set

Domain is an open connected subset of a complex plane.

"A hyperbolic component H of Mandelbrot set is a maximal domain (of parameter plane) on which f_c\, has an attracting periodic orbit.

A center of a H is a parameter  c_0 \in H\, ( or point of parameter plane ) such that the corresponding periodic orbit has multiplier= 0." [73]

A hyperbolic component is narrow if it contains no component of equal or lesser period in its wake [74]

Limb[edit]

13/34 limb and wake on the left image

p/q limb is a part of Mandelbrot set contained inside p/q wake

Wake[edit]

Wake is the region of parameter plane enclosed by its two external rays landing on the same root point.

Components of dynamical plane[edit]

In case of Siegel disc critical orbit is a boundary of component containing Siegel Disc.

Domain[edit]

Domain in mathematical analysis it is an open connected set

Planar set[edit]

a non-separating planar set is a set whose complement in the plane is connected.[75]

Target set[edit]

How target set is changing along internal ray 0

Elliptic case[edit]

Target set in elliptic case = inner circle

For the elliptic dynamics, when there is a Siegel disc, the target set is an inner circle

Hyperbolic case[edit]

Infinity is allways hyperbolic attractor for forward iteration of polynomials. Target set here is an exterior of any shape containing all point of Julia set ( and it's interior). There are also other hyperbolic attractors.


In case of forward iteration target set T\, is an arbitrary set on dynamical plane containing infinity and not containing points of filled Julia set.

For escape time algorithms target set determines the shape of level sets and curves. It does not do it for other methods.

Exterior of circle[edit]

This is typical target set. It is exterior of circle with center at origin z = 0 \, and radius =ER :


T_{ER}=\{z:abs(z) > ER \} \,

Radius is named escape radius ( ER ) or bailout value.

Circle of radius=ER centered at the origin is :  \{z:abs(z) = ER \} \,

Exterior of square[edit]

Here target set is exterior of square of side length s\, centered at origin

T_s=\{z: abs(re(z)) > s  ~~\mbox{or}~~  abs(im(z))>s \} \,

Parabolic case[edit]

In the parabolic case target set is a petal


Trap[edit]

Trap is an another name of the target set. It is a set which captures any orbit tending to point inside the trap ( fixed / periodic point ).

Test[edit]

Bailout test[edit]

Two sets after bailout test: escaping white and non-escaping black
Distance to fixed point for various types of dynamics

It is used to check if point z on dynamical plane is escaping to infinity or not. It allows to find 2 sets :

  • escaping points ( it should be also the whole basing of attraction to infinity)[76]
  • not escaping points ( it should be the complement of basing of attraction to infinity)

In practice for given IterationMax and Escape Radius :

  • some pixels from set of not escaping points may contain points that escape after more iterations then IterationMax ( increase IterMax )
  • some pixels from escaping set may contain points from thin filaments not choosed by maping from integer to world ( use DEM )


If z_n is in the target set T\, then z_0 is escaping to infinity ( bailouts ) after n forward iterations ( steps).[77]

The output of test can be :

  • boolean ( yes/no)
  • integer : integer number (value of the last iteration)

References[edit]

  1. argument of complex number
  2. A Method to Solve the Limitations in Drawing External Rays of the Mandelbrot Set M. Romera, G. Pastor, A. B. Orue, A. Martin, M.-F. Danca, and F. Montoya
  3. Unit circle in wikipedia
  4. The Road to Chaos is Filled with Polynomial Curves by Richard D. Neidinger and R. John Annen III. American Mathematical Monthly, Vol. 103, No. 8, October 1996, pp. 640-653
  5. Hao, Bailin (1989). Elementary Symbolic Dynamics and Chaos in Dissipative Systems. World Scientific. ISBN 9971-5-0682-3. http://power.itp.ac.cn/~hao/. 
  6. M. Romera, G. Pastor and F. Montoya, "Misiurewicz points in one-dimensional quadratic maps", Physica A, 232 (1996), 517-535. Preprint
  7. wikipedia : Jordan curve theorem
  8. Modeling Julia Sets with Laminations: An Alternative Definition by Debra Mimbs
  9. Laminations of the unit disk with irrational rotation gaps by John C. Mayer
  10. Rational maps represented by both rabbit and aeroplane matings Thesis submitted in accordance with the requirements of the University of Liverpool for the degree of Doctor in Philosophy by Freddie R. Exall July 2010
  11. Rational maps represented by both rabbit and aeroplane matings Thesis submitted in accordance with the requirements of the University of Liverpool for the degree of Doctor in Philosophy by Freddie R. Exall July 2010
  12. Iterated Monodromy Groups of Quadratic Polynomials, I Laurent Bartholdi, Volodymyr V. Nekrashevych
  13. GROWTH OF GROUPS DEFINED BY AUTOMATA : ASHLEY S. DOUGHERTY, LYDIA R. KINDELIN, AARON M. REAVES, ANDREW J. WALKER, AND NATHANIEL F. ZAKAHI
  14. Multiplier at wikipedia
  15. Iterated function (map) in wikipedia
  16. evolution function
  17. the discrete nonlinear dynamical system
  18. Complex quadratic map in wikipedia
  19. Michael Yampolsky, Saeed Zakeri : Mating Siegel quadratic polynomials.
  20. Mandel: software for real and complex dynamics by Wolf Jung
  21. wikipedia : Dyadic transformation
  22. lavaurs' algorithm in Haskell with SVG output by Claude Heiland-Allen
  23. SYMBOLIC DYNAMICS AND SELF-SIMILAR GROUPS by VOLODYMYR NEKRASHEVYCH
  24. Poincaré map
  25. General principles of chaotic dynamics by P.B. Persson , C.D. Wagner
  26. Conformal Geometry and Dynamics of Quadratic Polynomials Mikhail Lyubich
  27. wikipedia : Rotation number
  28. scholarpedia : Rotation_theory
  29. The Fractal Geometry of the Mandelbrot Set II. How to Count and How to Add Robert L. Devaney
  30. Complex systems simulation Curso 2012-2013 by Antonio Giraldo and María Asunción Sastre
  31. wikipedia : orbit (dynamics)
  32. Wikipedia : Complex quadratic polynomial - Critical point
  33. MandelOrbits - A visual real-time trace of Mandelbrot iterations by Ivan Freyman
  34. wikipedia : Periodic points of complex quadratic mappings
  35. M. Romera, G. Pastor, and F. Montoya : Multifurcations in nonhyperbolic fixed points of the Mandelbrot map. Fractalia 6, No. 21, 10-12 (1997)
  36. Burns A M : Plotting the Escape: An Animation of Parabolic Bifurcations in the Mandelbrot Set. Mathematics Magazine, Vol. 75, No. 2 (Apr., 2002), pp. 104-116
  37. Ouadratic-like maps and Renormalization by Nuria Fagella
  38. scholarpedia : Periodic Orbit for a Map
  39. wikipedia : Complex_quadratic_polynomial - Planes
  40. Alternate Parameter Planes by David E. Joyce
  41. mu-ency : exponential map by R Munafo
  42. Exponential mapping and OpenMP by Claude Heiland-Allen
  43. Linas Vepstas : Self Similar?
  44. the flattened cardioid of a Mandelbrot by Tom Rathborne
  45. Stretching cusps by Claude Heiland-Allen
  46. Twisted Mandelbrot Sets by Eric C. Hill
  47. doubling bifurcations on complex plane by E Demidov
  48. On biaccessible points in the Julia set of the family z(a+z^{d}) by Mitsuhiko Imada
  49. Surgery in Complex Dynamics by Carsten Lunde Petersen, online paper
  50. Siegel disks by Xavier Buff and Arnaud Ch ́ritat e Univ. Toulouse Roma, April 2009
  51. wikipedia : Critical point (mathematics)
  52. Java program by Dieter Röß showing result of changing initial point of Mandelbrot iterations
  53. Cut point in wikipedia
  54. On local connectivity for the Julia set of rational maps : Newton’s famous example By P. Roesch
  55. muency : feigenbaum point
  56. On Periodic and Chaotic Regions in the Mandelbrot Set by G. Pastor , M. Romera, G. Álvarez, D. Arroyo and F. Montoya
  57. fractal-faq : section 6
  58. Period doubling and Feigenbaum's scaling be E Demidov
  59. wikipedia : Misiurewicz point
  60. G. Pastor, M. Romera, G. Álvarez, D. Arroyo and F. Montoya, "On periodic and chaotic regions in the Mandelbrot set", Chaos, Solitons & Fractals, 32 (2007) 15-25
  61. http://www.mndynamics.com/indexp.html%7C program Mandel by Wolf Jung , demo 2 page 3
  62. GROWTH OF GROUPS DEFINED BY AUTOMATA : ASHLEY S. DOUGHERTY, LYDIA R. KINDELIN, AARON M. REAVES, ANDREW J. WALKER, AND NATHANIEL F. ZAKAHI
  63. wikipedia : Orbit portrait
  64. CANTOR BOUQUETS, EXPLOSIONS, AND KNASTER CONTINUA: DYNAMICS OF COMPLEX EXPONENTIALS by Robert L. Devaney Publicacions Matematiques, Vol 43 (1999), 27–54.
  65. wikipedia : Conformal radius
  66. scholarpedia : Quadratic Siegel disks
  67. Julia Sets of Complex Polynomials and Their Implementation on the Computer by Christoph Martin Stroh
  68. fractalforums: bounding circle of julia sets by knighty
  69. wikipedia : Sequence
  70. wikipedia : series
  71. Mandel Set Combinatorics : Principal Series
  72. wikipedia : Continuum in set theory
  73. Surgery in Complex Dynamics by Carsten Lunde Petersen, online paper
  74. Internal addresses in the Mandelbrot set and irreducibility of polynomials by Dierk Schleicher
  75. A. Blokh, X. Buff, A. Cheritat, L. Oversteegen The solar Julia sets of basic quadratic Cremer polynomials, Ergodic Theory and Dynamical Systems , 30 (2010), #1, 51-65
  76. wikipedia : Escaping set
  77. fractint doc : bailout