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9 votes
1 answer
519 views

Are any embeddings $[0,1]\to\mathbb{R}^3$ topologically equivalent?

Suppose we are given embeddings $f_1,f_2:[0,1]\to\mathbb R^3$. Does there exist a homeomorphism $g:\mathbb R^3\to\mathbb R^3$ such that $g\circ f_1=f_2$? This question seems to be classical eighty ...
Andrey Ryabichev's user avatar
22 votes
3 answers
3k views

Cardioid-looking curve, does it have a name?

The curve, given in polar coordinates as $r(\theta)=\sin(\theta)/\theta$ is plotted below. This is similar to the classical cardioid, but it is not the same curve (the curve above is not even ...
Per Alexandersson's user avatar
5 votes
0 answers
103 views

wild julia sets

Using the Baire category theorem, we may show that most simple closed curves satisfy the following property: any segment between an interior point and an exterior point of the curve intersects the ...
coudy's user avatar
  • 18.7k
15 votes
0 answers
330 views

How much smoothness does the tennis ball theorem need?

The tennis ball theorem states that a smooth-enough curve that bisects the surface area of a sphere must have at least four inflection points. There are plenty of sources on this but most of them are ...
David Eppstein's user avatar
7 votes
4 answers
4k views

Generating random curves with fixed length and endpoint distance

Are algorithms already known, that generate (arbitrarily good approximations of) random curves, w.l.o.g. with unit length, and joining endpoints $(0,0)$ and $(\alpha,0)$ with $\alpha \lt1$ given? The ...
Manfred Weis's user avatar
  • 13.2k
1 vote
1 answer
64 views

Unbounded convex domains in 2D

Let $\gamma$ be a smooth planar curve. Assume that $\gamma$ divides the plane into two domains and, it addition, that one of these domains is unbounded and convex. What can be said about the behavior ...
poupy's user avatar
  • 175