I have been studying the
Mandelbrot Set for a number of years, and during that time I've learned
many wonderful things. The Set features a filligree of interwoven
spiral patterns in seemingly endless variations. But it turns out
that the branch points and centers of spirals display a mathematical
regularity that makes them Misiurewicz points - places where the
generating function does not immediately repeat, but eventually falls
into a repeating pattern. Such points are called pre-periodic,
and they are classified by how long they take to repeat and how often
they repeat thereafter. So how do we find them?
When we look at the generating
equation for the Mandelbrot Set and Julia Sets, it reads `z=z^2+c`
and this becomes `z=z^2+z`, or more specifically `z_n=z_(n-1)+z_0`
in the case of `cc(M)`. So we expect that the Misiurewicz
points will have terms of this same form, repeated a number
of times on either side of the equation. One such point of
interest satisfies the equation `((c^2+c)^2+c)^2+c=(c^2+c)^2+c` where
`c in bbb(C)` - the complex numbers*. We can expand this out to
get `c^8+4c^7+6c^6+6c^5+5c^4+2c^3+c^2+c=c^4+2c^3+c^2+c` by squaring
the terms inside the parentheses and then combining like factors.
When we solve for `c` we get two results with imaginary components.
`c=(sqrt(11)/3^(3/2)-17/27)^(1/3)*((sqrt(3)i)/2-1/2)-(2*(-(sqrt(3)i)/2-1/2))/(9*(sqrt(11)/3^(3/2)-17/27)^(1/3))-2/3`
and
There is a trivial solution
(which is actually a periodic or repeating point).
But the solution we are interested is
a non-trivial one where `c in bbb(R)` - a Real numbered value.
We note that the expression `sqrt(11)/3^(3/2)-17/27` can be simplified. Since `3^3=27`, this becomes `sqrt(11)/sqrt(27)` and using the fractions of square roots rule, we can write this as `sqrt(11/27)`. Then our solution becomes
This has a numerical value around
-1.5436890126920763615708559717993But can we get closer to an exact value?
This extended precision result may suffice:
-1.543689012692076361570855971801747986525203297650983935240 804037831168673927973866485157914576059125462120829226367060 189278756463322141011522909218905292722992781697157582950422 170089518563410700385200128000282366477261779986908996884104 614976976927086847969611978920181446128991348585592145309524 153482664595734117098522176434389326263543393937637861596321 991246778909541806274987275657314799920191066093455727443186 409799911554184677317541006847088177067596744933391559037024 490072743842093947624299476858021814236680891765387460029177 563608220435803992788777820556050367509668431452581000660479 923719409341669347