Christian Blatter

ETH Zurich (Switzerland)

math.ethz.ch/~blatter

Age: 79

5h
answered Prove $d(x,y)=\arctan|x-y|$ is a metric
10h
revised Volume of a sphere with two cylindrical holes.
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11h
comment Volume of a sphere with two cylindrical holes.
@coffeemath: You are right. The answer will be deleted in due course.
11h
revised Volume of a sphere with two cylindrical holes.
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15h
answered Volume of a sphere with two cylindrical holes.
16h
answered Is the set of continuous functions from $[0,1] \rightarrow \mathbb{R}$ closed in the same set from $[0,1]$ to $\mathbb{C}$?
1d
answered Polygonal chain in a rectangular parallelepiped
1d
answered Why does the slope of a smooth simple closed curve have winding number one?
1d
comment Why does the slope of a smooth simple closed curve have winding number one?
Here is a proof of the theorem by one of the masters. I'm sure it is as simple as it can get: ma.utexas.edu/users/dafr/M365G/Readings/Chern.pdf
1d
answered Number Theory Question - prove no integer solutions
2d
answered Prove that $\frac{dN}{ds}=-\kappa T$
2d
answered To check if (0,0) is local minima for$F ( x, y) = x (x - 2y^{2}) $
2d
revised Rigorous proof for a maximization problem
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2d
revised Rigorous proof for a maximization problem
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2d
answered Rigorous proof for a maximization problem
Jan
22
comment area-preserving iff $|\det |=+1$
@user36772: I suggest you formulate this as a separate question, because it is an interesting problem in itself.
Jan
22
revised "Hall of mirrors" OR "wrapped plane" - Problem
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Jan
22
revised "Hall of mirrors" OR "wrapped plane" - Problem
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Jan
22
answered How many arrangements do we have?
Jan
22
revised area-preserving iff $|\det |=+1$
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