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6 votes
0 answers
98 views

Rigid plane curves

A curve is a continuous one-to-one image of the real line $\mathbb R$. A space $X$ is rigid if the only homeomorphism of $X$ onto itself is the identity. Is there a rigid curve in the plane? I am ...
25 votes
1 answer
3k views

Why is it so hard to prove Toeplitz' conjecture?

I'm a layman in mathematics, so please excuse me in advance for anything in this question that may be inappropriate :D. Well: Four years ago, I was reading (and working to solve the puzzles on) ...
1 vote
2 answers
397 views

When is the inside of a Jordan curve open? [closed]

I'm working purely on intuition here. The Jordan curve theorem states that a Jordan curve separates the plane into a bounded component and an infinite component. For toy curves, it seems like this ...
-2 votes
1 answer
587 views

Is the conjecture true for n-sphere $(n>2)$? [closed]

This is higher dimension conjecture of Problem 3845 in Crux Mathematicorum and Theorem 2 in here: PS: This figure is very nice, this is also generalization of Brianchon’s theorem, The Pascal theorem, ...
0 votes
2 answers
129 views

Planar curves identical to their inverses

Is the right strophoid the only planar curve $C$ whose inverse curve w.r.t. some circle (in this case: centered on the origin) is identical to $C$?               &...
1 vote
0 answers
109 views

Intersection points of closed curves inscribed in a convex polygon

Suppose that I have two distinct simple closed curves, $C_1$ & $C_2$, and each is inscribed in a convex polygon, D. By inscribed, I mean tangent to each side of D. In particular, I am most ...
13 votes
1 answer
699 views

Including a Jordan arc into a Jordan loop (Can the Magi go home by another way?)

The title refers, of course, to Matthew (2:12) ''And being warned in a dream not to return to Herod, they departed to their own country by another way''. To be honest, it is not that specific ...