35,363 reputation
12443
bio website jungenschaft-hohenstaufen.de
location Berlin, Germany
age 33
visits member for 3 years, 4 months
seen Jan 13 at 10:49

Aug
8
reviewed Leave Closed is it possible for some infinite cardinality of numbers to exhibit $x \cdot x = 0$ while other numbers $y \cdot y \neq 0$?
Aug
8
comment Separability of the space of bounded uniformly continuous functions
Passing through the Stone-Cech compactification does not help in general, as the latter is not metrizable in general, and hence $C(\beta X)$ fails to be seperable (note, that for $K$ compact Hausdorff $C(K)$ is separable iff $K$ is metrizable).
Aug
8
reviewed Reject How much gas does a car use to carry its own gas?
Aug
8
reviewed Leave Open How prove that $\max(|f(1)|,|f(2)|,|f(3)|,|f(4)|)\geq \frac{1}{2}$ if $f(x) = \cos(Ax)+\cos(Bx)$?
Aug
8
reviewed No Action Needed Sum of products of binomial coefficients
Aug
8
reviewed Looks OK dimension of $\mathbb{C}$ over $\mathbb{Q}$
Aug
8
reviewed Edit Brackets with a summation
Aug
8
revised Brackets with a summation
replaced image by TeX.
Aug
8
reviewed Close What is the oldest open problem in geometry?
Aug
8
reviewed Leave Open $E \subseteq [0, 1]$, $m(E) > 0$. Show that there are $\alpha$ and $\beta$ such that $\alpha, \alpha + \beta, \alpha + 2\beta \in E$.
Aug
8
reviewed Leave Open Show that $ \frac{2+\ln a }{2}\lt\frac{a-1}{\ln a} \lt \frac{1+a}{2}$ becomes $ \frac{2(a-1)}{a+1}\lt\ln a \lt -1 + \sqrt{2a-1}$
Aug
8
reviewed Leave Open a theory $(x,+,\cdot)$ satisfies $x \cdot x=0$ and $x \cdot (y \cdot z)=(x\cdot y)\cdot z$
Aug
8
reviewed Close Prove this linear map $(Tf)(x) = x^2f(x)$ is injective and find the null space
Aug
7
revised What can be the possible rank of adjoint of matrix of order n?
This is not (functional-analysis)
Aug
7
reviewed Looks OK What is the maximum y-value of the following function?
Aug
7
reviewed Close Finding parametric distance on quadratic curve from given $(x,y)$ point
Aug
7
reviewed Leave Open How to find rank of linear operator T on inner product space
Aug
7
reviewed Looks OK Is there an odd integer other than 1 that is the sum of its divisors?
Aug
7
reviewed Looks OK Limit Question: $\lim_{x \rightarrow a} \frac{3}{x}$. What does the “a” represent?
Aug
7
comment Limit Question: $\lim_{x \rightarrow a} \frac{3}{x}$. What does the “a” represent?
This not an answer to the question asked in my humple opinion. The OP does not asked for the value of the limit, but for the "role" of $a$ ...