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Joseph O'Rourke
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I am seeking a function $f: \mathbb{R}^3 \to \mathbb{R}^3$ that has these properties:

(1) When iterated $n$ times starting from some $p$, connecting the points in order with segments and closing last to first,

$$(p, f(p), f^2(p), \ldots, f^n(p), p)$$

results in a simple (non-self-intersecting) closed polygonal cycle $K$.

(2) When $K$ is viewed as a knot, it is highly tangled, e.g., it has large crossing number, or large unknotting number. The tangledness, however defined, should increase with $n$, the faster the better.

(3) These properties should hold for infinitely many $n$.

Expressed differently, I would like a way to generate an infinite variety of increasingly tangled stick knots via a simple function iteration. My requirements are a bit loose, as I just want to simply generate knotty examples. Likely some weaving is known to accomplish this...?
          Tangled Knot http://cs.smith.edu/%7Eorourke/MathOverflow/TangledKnotFunction.jpgTangled Knot
(This question is intellectually related to an earlier question, "Complexity of random knot with vertices on sphere.")

I am seeking a function $f: \mathbb{R}^3 \to \mathbb{R}^3$ that has these properties:

(1) When iterated $n$ times starting from some $p$, connecting the points in order with segments and closing last to first,

$$(p, f(p), f^2(p), \ldots, f^n(p), p)$$

results in a simple (non-self-intersecting) closed polygonal cycle $K$.

(2) When $K$ is viewed as a knot, it is highly tangled, e.g., it has large crossing number, or large unknotting number. The tangledness, however defined, should increase with $n$, the faster the better.

(3) These properties should hold for infinitely many $n$.

Expressed differently, I would like a way to generate an infinite variety of increasingly tangled stick knots via a simple function iteration. My requirements are a bit loose, as I just want to simply generate knotty examples. Likely some weaving is known to accomplish this...?
          Tangled Knot http://cs.smith.edu/%7Eorourke/MathOverflow/TangledKnotFunction.jpg
(This question is intellectually related to an earlier question, "Complexity of random knot with vertices on sphere.")

I am seeking a function $f: \mathbb{R}^3 \to \mathbb{R}^3$ that has these properties:

(1) When iterated $n$ times starting from some $p$, connecting the points in order with segments and closing last to first,

$$(p, f(p), f^2(p), \ldots, f^n(p), p)$$

results in a simple (non-self-intersecting) closed polygonal cycle $K$.

(2) When $K$ is viewed as a knot, it is highly tangled, e.g., it has large crossing number, or large unknotting number. The tangledness, however defined, should increase with $n$, the faster the better.

(3) These properties should hold for infinitely many $n$.

Expressed differently, I would like a way to generate an infinite variety of increasingly tangled stick knots via a simple function iteration. My requirements are a bit loose, as I just want to simply generate knotty examples. Likely some weaving is known to accomplish this...?
          Tangled Knot
(This question is related to an earlier question, "Complexity of random knot with vertices on sphere.")

replaced http://mathoverflow.net/ with https://mathoverflow.net/
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I am seeking a function $f: \mathbb{R}^3 \to \mathbb{R}^3$ that has these properties:

(1) When iterated $n$ times starting from some $p$, connecting the points in order with segments and closing last to first,

$$(p, f(p), f^2(p), \ldots, f^n(p), p)$$

results in a simple (non-self-intersecting) closed polygonal cycle $K$.

(2) When $K$ is viewed as a knot, it is highly tangled, e.g., it has large crossing number, or large unknotting number. The tangledness, however defined, should increase with $n$, the faster the better.

(3) These properties should hold for infinitely many $n$.

Expressed differently, I would like a way to generate an infinite variety of increasingly tangled stick knots via a simple function iteration. My requirements are a bit loose, as I just want to simply generate knotty examples. Likely some weaving is known to accomplish this...?
          Tangled Knot http://cs.smith.edu/%7Eorourke/MathOverflow/TangledKnotFunction.jpg
(This question is intellectually related to an earlier question, "Complexity of random knot with vertices on sphereComplexity of random knot with vertices on sphere.")

I am seeking a function $f: \mathbb{R}^3 \to \mathbb{R}^3$ that has these properties:

(1) When iterated $n$ times starting from some $p$, connecting the points in order with segments and closing last to first,

$$(p, f(p), f^2(p), \ldots, f^n(p), p)$$

results in a simple (non-self-intersecting) closed polygonal cycle $K$.

(2) When $K$ is viewed as a knot, it is highly tangled, e.g., it has large crossing number, or large unknotting number. The tangledness, however defined, should increase with $n$, the faster the better.

(3) These properties should hold for infinitely many $n$.

Expressed differently, I would like a way to generate an infinite variety of increasingly tangled stick knots via a simple function iteration. My requirements are a bit loose, as I just want to simply generate knotty examples. Likely some weaving is known to accomplish this...?
          Tangled Knot http://cs.smith.edu/%7Eorourke/MathOverflow/TangledKnotFunction.jpg
(This question is intellectually related to an earlier question, "Complexity of random knot with vertices on sphere.")

I am seeking a function $f: \mathbb{R}^3 \to \mathbb{R}^3$ that has these properties:

(1) When iterated $n$ times starting from some $p$, connecting the points in order with segments and closing last to first,

$$(p, f(p), f^2(p), \ldots, f^n(p), p)$$

results in a simple (non-self-intersecting) closed polygonal cycle $K$.

(2) When $K$ is viewed as a knot, it is highly tangled, e.g., it has large crossing number, or large unknotting number. The tangledness, however defined, should increase with $n$, the faster the better.

(3) These properties should hold for infinitely many $n$.

Expressed differently, I would like a way to generate an infinite variety of increasingly tangled stick knots via a simple function iteration. My requirements are a bit loose, as I just want to simply generate knotty examples. Likely some weaving is known to accomplish this...?
          Tangled Knot http://cs.smith.edu/%7Eorourke/MathOverflow/TangledKnotFunction.jpg
(This question is intellectually related to an earlier question, "Complexity of random knot with vertices on sphere.")

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Joseph O'Rourke
  • 150.9k
  • 36
  • 358
  • 958

I am seeking a function $f: \mathbb{R}^3 \to \mathbb{R}^3$ that has these properties:

(1) When iterated $n$ times starting from some $p$, connecting the points in order with segments and closing last to first,

$$(p, f(p), f^2(p), \ldots, f^n(p), p)$$

results in a simple (non-self-intersecting) closed polygonal cycle $K$.

(2) When $K$ is viewed as a knot, it is highly tangled, e.g., it has large crossing number, or large unknotting number. The tangledness, however defined, should increase with $n$, the faster the better.

(3) These properties should hold for infinitely many $n$.

Expressed differently, I would like a way to generate an infinite variety of increasingly tangled stick knots via a simple function iteration. My requirements are a bit loose, as I just want to simply generate knotty examples. Likely some weaving is known to accomplish this...?
          Tangled Knot http://cs.smith.edu/%7Eorourke/MathOverflow/TangledKnotFunction.jpg
(This question is intellectually related to an earlier question, "Complexity of random knot with vertices on sphere.")

I am seeking a function $f: \mathbb{R}^3 \to \mathbb{R}^3$ that has these properties:

(1) When iterated $n$ times starting from some $p$, connecting the points in order with segments and closing last to first,

$$(p, f(p), f^2(p), \ldots, f^n(p), p)$$

results in a simple (non-self-intersecting) closed polygonal cycle $K$.

(2) When $K$ is viewed as a knot, it is highly tangled, e.g., it has large crossing number, or large unknotting number. The tangledness, however defined, should increase with $n$.

(3) These properties should hold for infinitely many $n$.

Expressed differently, I would like a way to generate an infinite variety of increasingly tangled stick knots via a simple function iteration. My requirements are a bit loose, as I just want to simply generate knotty examples. Likely some weaving is known to accomplish this...?
          Tangled Knot http://cs.smith.edu/%7Eorourke/MathOverflow/TangledKnotFunction.jpg
(This question is intellectually related to an earlier question, "Complexity of random knot with vertices on sphere.")

I am seeking a function $f: \mathbb{R}^3 \to \mathbb{R}^3$ that has these properties:

(1) When iterated $n$ times starting from some $p$, connecting the points in order with segments and closing last to first,

$$(p, f(p), f^2(p), \ldots, f^n(p), p)$$

results in a simple (non-self-intersecting) closed polygonal cycle $K$.

(2) When $K$ is viewed as a knot, it is highly tangled, e.g., it has large crossing number, or large unknotting number. The tangledness, however defined, should increase with $n$, the faster the better.

(3) These properties should hold for infinitely many $n$.

Expressed differently, I would like a way to generate an infinite variety of increasingly tangled stick knots via a simple function iteration. My requirements are a bit loose, as I just want to simply generate knotty examples. Likely some weaving is known to accomplish this...?
          Tangled Knot http://cs.smith.edu/%7Eorourke/MathOverflow/TangledKnotFunction.jpg
(This question is intellectually related to an earlier question, "Complexity of random knot with vertices on sphere.")

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Joseph O'Rourke
  • 150.9k
  • 36
  • 358
  • 958
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