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Fractal Math, Chaos Theory & Research => General Discussion => Topic started by: Chillheimer on April 25, 2016, 12:34:33 PM




Title: How do you read the --> in z-->z²+c
Post by: Chillheimer on April 25, 2016, 12:34:33 PM
Hi!
I'm making a short movie about fractals and have to read the m-set formula.
do you say z equals z²+c?
or does the arrow have its own word?
Thx in advance!


Title: Re: How do you read the --> in z-->z²+c
Post by: claude on April 25, 2016, 01:06:00 PM
"z equals z squared plus c" is wrong (it defines a quadratic equation with two solutions).

"z maps to z squared plus c" is probably what I would say, or modifying or leaving out the "maps" depending on context ("repeated iterations of the mapping 'z to z squared plus c'" could work), although the LaTeX symbol is slightly different: \mapsto \mapsto, vs \to \to

alternatively subscripts with iteration can use an explicit equals:  "z n plus one equals z n squared plus c"


Title: Re: How do you read the --> in z-->z²+c
Post by: kram1032 on April 25, 2016, 01:21:15 PM
"is mapped to" or "is replaced by" or "is substituted for"
The difference between
\left(1\right) \ \ \ z \to z^2+c
and
\left(2\right) \ \ \ z=z^2+c
is that \left(1\right) refers to the M-set at any given iteration step - it's valid for all of them, whereas \left(2\right) talks about the limit set. Only in the limit of infinitely many iterations is it actually true that z=z^2+c.

Although claude is right that usually z=z^2+c would be considered a quadratic equation with two solutions. It only works as I described if you consider z to be the entire Julia- or Mandelbrot set, rather than a single point which only holds true for a few trivial cases (namely the above mentioned solutions of the quadratic equation).


Title: Re: How do you read the --> in z-->z²+c
Post by: quaz0r on April 25, 2016, 01:34:43 PM
all of that is rather awkward for casually speaking the words...  couldnt one say Zn+1 equals Zn^2 + c, or for that matter, just say z equals z^2 + c, the fact that you are referring to how each iteration is calculated either being implied or explicitly stated, as opposed to deffining a quadractic euqation (claude hasnt had his coffee yet)   :)   i think the casual listener probably won't assume you are wrongly defining a quadratic equation and feel all horribly offended and led astray..


Title: Re: How do you read the --> in z-->z²+c
Post by: kram1032 on April 25, 2016, 01:49:10 PM
In how far is saying "z maps to z squared plus c" any more or less awkward than saying "z equals z squared plus c" and how is it any more awkward than explicitly mentioning the iteration variable "z n plus one equals z n squared plus c"? Why mention variables that are only used internally for housekeeping? Explicitly mentioning the iteration variables is both awkward and ambiguous.
"z equals z squared plus c" will rarely but occasionally be ambiguous.
"z maps to z squared plus c" never is ambiguous.


Title: Re: How do you read the --> in z-->z²+c
Post by: Chillheimer on April 26, 2016, 10:45:35 AM
Thx guys, "maps to" is exactly what I was looking for.
Falls jemand die deutsche Übersetzung kennt, die wüsste ich auch gerne..


Title: Re: How do you read the --> in z-->z²+c
Post by: hobold on April 26, 2016, 11:34:43 AM
Thx guys, "maps to" is exactly what I was looking for.
Falls jemand die deutsche Übersetzung kennt, die wüsste ich auch gerne..
"z wird abgebildet auf z² + c"