charmd

Member for 7 years, 7 months
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France

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real-analysis

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Score Activity Newest

27

Is a function periodic $f(x) = \cos (x) +\cos(x^2)$

Feb 16, 2018

13

Example of a function differentiable in a point, but not continuous in a neighborhood of the point?

Apr 21, 2016

11

$A^{64}=A^{27}=I$, prove $A=I$

Apr 9

10

Is this a valid argument for proving that a sum of reciprocals is irrational?

Apr 25, 2016

10

If $f'(x)>0$ on $E$ , where $m(E)>0,$ then $m(f(E))>0$

Jan 11, 2017

Questions

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23

Is a convex function always continuous?

Oct 19, 2018

17

Function $f$ such that $|f(x)-f(y)| \ge \sqrt{|x-y|}$

Feb 16, 2017

15

Power series converging at $1$ with all derivatives zero

Feb 18, 2018

12

Is a product of derivatives still a derivative?

Dec 28, 2016

8

Symmetric strategy for 100 prisoners and a light bulb problem

Apr 4, 2019

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real-analysis

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39

posts

measure-theory

43

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19

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sequences-and-series

43

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17

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trigonometry

35

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6

posts

algebra-precalculus

35

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5

posts

Reputation

+20

Is a convex function always continuous?

+10

Negative moments of Marchenko-Pastur law

+40

Let $T\in M_m(\mathbb{C})$ with $r(T)=1$. Is it true that $\lim \frac{\lVert T^{n+1}\rVert}{\lVert T^n\rVert}=1$?

+10

$A^{64}=A^{27}=I$, prove $A=I$

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