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University of Florence


May
27
comment Urn problem for pairs of black balls
Please correct the phrase "1 consecutive pairs of black balls". Maybe you mean "at least two consecutive black balls"?
May
27
reviewed Approve suggested edit on Urn problem for pairs of black balls
May
25
answered Is it true that $a$ and $b$ should be disjoint permutations?
May
25
answered Is $\left\{x\mid x\text{ is a countable set}\right\}$ a set?
May
25
answered Confusion over Matrix rotation
May
25
answered Error with thinking about shortest distance between two lines in three space
May
25
answered How to show a trapezium $ABCD$ with sides $AD$ and $CD$ parallel satisfies $AD+BC=AB+DC$?
May
18
comment Differentiability of a function and continuity of its derivative.
what rhd/rhl means?
May
13
answered Let f(z) be analytic on the unit disk D.f(r) = max{| f(z)| : |z| = r}. Does f'(r) > 0, if f is not a constant?
May
11
comment Trying to prove M is a Manifold of certain dimension
Yes. $n=3$ hence $n-1=2$
May
11
comment Trying to prove M is a Manifold of certain dimension
If you find a solution $Df=0$ on $f=0$ then you are in trouble... in that case I would try to understand what is happening in the given point and see if the manifold can be decomposed in some way to simpler equations.
May
11
revised Trying to prove M is a Manifold of certain dimension
added 201 characters in body
May
11
answered Trying to prove M is a Manifold of certain dimension
May
6
comment moebius transforms preserve sum of signed curvatures
please look at the update... have you some other hint?
May
6
revised moebius transforms preserve sum of signed curvatures
added 743 characters in body
May
5
comment moebius transforms preserve sum of signed curvatures
You are right... but at least I can suppose one of the three circles is $|z|=1$, don't I?
May
5
comment moebius transforms preserve sum of signed curvatures
I think you are right, the point is to reduce the problem to a single inversion and to use isometric transformation to reduce the problem. I would reduce to $z=0$ instead of $z=1$, what do you think? The point $z=0$ will go to infinity, but I only have to measure the curvature of the three circles... I will try the computation.
Apr
28
asked moebius transforms preserve sum of signed curvatures
Apr
15
answered Are there contradictions in math?
Apr
15
answered I want, by the use of the equation of the line in complex plane, to find the slope and x intercept in x-y plane