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Stylistic improvements.
Peter Heinig
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How to prove that there does not exist any plane isotopy from the logarithmic spiral onto the real line?

Questions.

(0) How would you prove, in usual topology, the following assertion:

(A) There does not exist any plane isotopy carrying the subset $S=\{ (\exp(t)\ \cos(t),\exp(t)\ \sin(t)|\quad t\in\mathbb{R}\}\subseteq\mathbb{R}^2$ onto the subset $R=\{ (t,0)|\quad t\in\mathbb{R}\}\subseteq\mathbb{R}^2$.

(1) Independent of (0), in a bibliographic/reference-requestish vein:

(B) In what literature references does (something equivalent to) (A) recognizably appear? (I'm interested in as many relevant references as possible, in any of the media: book, lecture notes, research paper, website.)

Remarks.

  • In $A$, all technical terms are standard terms of basic topology nowadays. The term plane isotopy would in some contexts often called by the more general term ambient isotopy. For what it's worth, a definition of the central notion here is the following.

Let

$\eta_S\colon \mathbb{R}\rightarrow\mathbb{R}^2$ be given by $\eta_S(t) = (\exp(t)\cdot\cos(t),\exp(t)\cdot\sin(t))$,

and

$\eta_R\colon \mathbb{R}\rightarrow\mathbb{R}^2$ be given by $\eta_R(t) = (t,0)$.

Then a plane isotopy is any continuous set-map

$\theta\colon \mathbb{R}^2\times[0,1]\rightarrow\mathbb{R}^2$

satisfying the three axioms

(A.0) for all $v\in\mathbb{R}^2$, $v=\theta(v,0)$,

(A.1) for all $t\in[0,1]$, $v\mapsto\theta(v,t)$ defines a homeomorphism $\mathbb{R}^2\rightarrow\mathbb{R}^2$,

(A.2) $(v\mapsto \theta(v,1))\circ\eta_S = \eta_R$, equal as set-maps.

  • I am less, but also, interested in the correct answer here, more in different writing- and proof-styles, some more efficient than others, localized at this very question.

  • Of course, $S\subseteq\mathbb{R}^2$ 'looks' something like the blue line in the following illustration: enter image description here

(Made with Sage.)

  • Motivation for this question is that (A) came up in research about (three-connected) infinite planar graphs, and I need to know more about and around it.
Peter Heinig
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  • 47