109,501 reputation
698199
bio website von-eitzen.de/math/tntrep.xml
location Bonn, Germany
age 48
visits member for 1 year, 11 months
seen 2 days ago

I did study math and had a knack for it, but I am sooo out of that business now ...


Aug
17
answered Prove that $\lim_{x\to\infty}f''(x)=0$ if $\lim_{x\to\infty}f(x)=T$ and $\lim_{x\to\infty}f'''(x)=0$.
Aug
16
answered Usage of the term “Free”
Aug
15
comment Secretary problem *without* each ordering equally likely
The assmptions need to be made more precise. For example, if we assume strict descending order the nalways pick the first :)
Aug
15
comment Mersenne Numbers 1+4k
+1 for this surprisingly direct method.
Aug
15
comment How prove this $Z(H)\neq 1$, if for any $g\in G\setminus H, H\cap H^g=1$
Is "for any" = "for every" or "for some"?
Aug
14
reviewed Leave Closed A Question about Doctoral Theses in Mathematics
Aug
14
answered Bijection from $\mathbb{R}$ to the set of all infinite subsets of $\mathbb{R}$?
Aug
14
answered existence of some algebraic closure
Aug
14
comment Prove that every subset of $\mathbb{R}$ is compact in the finite complement topology.
For an alternative proof, among all nonempty finite subsets $I$ of $J$ consider one that minimizes the finite(!) number $|Y \setminus \bigcup_{\alpha\in I}A_\alpha|$
Aug
14
comment Clarification on The Trichotomy Law
@vajra78 Yes, exactly
Aug
14
answered Clarification on The Trichotomy Law
Aug
13
comment Finding the transfinite diameter of the level sets of complex logarithm
Maybe your regions are sufficiently "disklike" that you can approximate it with an inscribed and a circumscribed disk?
Aug
13
comment For a transitive permutation group $G,$ show that there is some $\sigma \in G$ such that $\sigma(a) \neq a$ for all $a \in A.$
Note that the claim B) does not require transitivity, nor finiteness of $A$, nor $|A|>1$. This reaises the suspicion that you miscopied the problem statement
Aug
13
comment Solving $x^3+y^3=x^2y^2+1$ in non-negative integers
$b\in\{b,\ldots\}$ does not look like much of a success
Aug
13
comment How to increase winning chance in lottery
Uniform without replacement, i.e. in the first draw, each number has the same probability $\frac1{36}$ to be drawn; then all remaining numbers have the same probability $\frac1{35}$ and so on. In effect, one of the $36\choose 6$ possible combinations is drawn uniformly, i.e. each combination has a chance of $\frac1{36\choose 6}$ of being drawn.
Aug
13
answered Help with exercise from the Category Theory Wikibook
Aug
13
answered What does it mean for a function to be uniquely determined by another function?
Aug
13
answered What is the value of $\displaystyle\lim_{n\to\infty}{\left(n-\left|n\right|\right)}$
Aug
13
comment How to increase winning chance in lottery
What is the random variable about which's distribution you ask?
Aug
13
comment $6n+1$ and $6n-1$ prime format
@RajShah Are you sure you are not getting timing problems already from I/O? There are about 48 million primes below $10^9$