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We study the paper "Dynamic analysis and control of a new hyperchaotic finance system"

It is given the following system

$$X'=Z+(Y-\alpha)X$$ $$Y'=1-\beta Y-X^2$$ $$Z'=-X-\gamma Z$$ with initial conditions $(X(0),Y(0),Z(0))=(1,2,3)$.

Where

X: interest rate

Υ:investment demand

Z: price index

$\alpha$: savings, $\beta$: cost per investment, $\gamma$: the absolute value of the elasticity of demand

One of the characteristics of systems with chaotic behavior is the so-called sensitive dependence on initial conditions. So we take now $(X(0),Y(0),Z(0))=(1.001,2.001,3.001)$. We notice that the new intial conditions differ in each coordinate by $10^{-3}$. Now I am trying to compare them on Mathematica but the plots it returns are identical. Is this possible?

MakePlot[{α_, β_, γ_}, {a_, b_, c_}, h_, 
  max_Integer] := 
 Module[{u, if}, 
  f[{x_, y_, z_}] := {z + (y - α)*x, 
    1 - β*y - x^2, -x - γ*z};
  u[0] = {a, b, c};
  Do[u[n + 1] = u[n] + h*f[u[n] + h/2*f[u[n]]], {n, 0, max}];
  if = Interpolation[Table[{n, u[n]}, {n, 0, max/h}]];
  Plot[if[t], {t, 0, 200}, PlotLegends -> Automatic,Frame -> True, ImageSize -> Medium]]

plot1 = MakePlot[{0.9, 0.2, 1.2}, {1, 3, 2}, 0.1, 1000 ]
plot2 = MakePlot[{0.9, 0.2, 1.2}, {1.001, 3.001, 2.001}, 0.1, 1000]
Show[{plot1, plot2}]

enter image description here enter image description here enter image description here

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  • $\begingroup$ Try with: MakePlot[{0.13, 0.18, 0.87}, {1, 2, 3}, 0.1, 1000] and MakePlot[{0.13, 0.18, 0.87}, {1.001, 2.001, 3.001}, 0.1, 1000]. $\endgroup$ Jan 29 at 0:15
  • $\begingroup$ @E.Chan-López the results of the graphs are still identical no? $\endgroup$ Jan 29 at 0:23
  • $\begingroup$ @E.Chan-López I can not see any difference between the plots $\endgroup$ Jan 29 at 0:32

1 Answer 1

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No, they are not identical. This is what I get:

MakePlot[{0.13, 0.18, 0.87}, {1, 2, 3}, 0.1, 1000]
MakePlot[{0.13, 0.18, 0.87}, {1.001, 3.001, 2.001}, 0.1, 1000]

enter image description here

enter image description here

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  • 1
    $\begingroup$ So i have to choose a bigger interval to see the differnce $\endgroup$ Jan 29 at 0:42
  • 1
    $\begingroup$ Definitely yes, you should see it at bigger intervals. $\endgroup$ Jan 29 at 0:46

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