Hagen von Eitzen
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 Aug 6 revised Let $V$ be a vector space, $W$ a supspace. Can we conclude that $W\oplus (V/W)$ and $V$ are isomorphic? added 2 characters in body Aug 6 revised Let $V$ be a vector space, $W$ a supspace. Can we conclude that $W\oplus (V/W)$ and $V$ are isomorphic? edited title Aug 6 revised Homeomorphism between two subspaces added 3 characters in body Aug 6 revised Homeomorphism between two subspaces added 3 characters in body Aug 6 comment values of a $\displaystyle\lim_{x \to -\infty} x^a$ What is $(-\pi)^\pi$? Aug 6 comment values of a $\displaystyle\lim_{x \to -\infty} x^a$ Your results so far are corretcd only for $a>0$. You can easily solve the remaining cases $a\in\mathbb Z\setminus\mathbb N$. How do you define $x^a$ for $x<0$ and $a\notin \mathbb Z$? Aug 6 comment Proof About Point and Triangles @miamiheatftw Well, ther is only one grou of four points if you have only $n=4$ points to begin with, hence the number of four-point-groups containing a triangle is trivially $\le 1$. Now if you have $k$ triangles, the claim is that the number of four-point-groups containing a triangle is $\le k(n-3)$. As $k(n-3)=k$, we have to show that the number of four-point-groups containing a triangle is $\le k$.As we already know that the number of four-point-groups containing a triangle is $\le1$, there is nothing to show for $k\ge 1$; of course there is also nothing to show for $k=0$. So all is fine. Aug 6 comment Can a non-constant two dimensional polynomial have a set of zero points of positive measure? Erm, so what is your question about? Non-isolated or positive measure? Aug 6 comment Can a non-constant two dimensional polynomial have a set of zero points of positive measure? Or try $f(x,y)=x$ Aug 6 comment Why is the argument of a complex number measured anticlockwise (from the positive real axis), rather than clockwise? Already in traditional (planar) geometry, anti-clockwise is the "mathematically positive" direction for angles, for labelling of polygons etc. I don't see how clockwise (or anti-clockwise) should be more intuitive. Aug 6 answered summation of a series in which each term is product of nth term of two sequence Aug 6 comment Show that $\sqrt{2}$ is irrational using the integer root theorem Alright, but slightly overdone I guess. The integer root theorem already says that the rational roots of $x^2-2$ are integers and divisors of $(-)2$. Aug 6 answered Proof About Point and Triangles Aug 6 revised Proof About Point and Triangles added 44 characters in body Aug 6 comment Proof About Point and Triangles The problem statement does not rule out $k=0$ or $k>{n\choose 3}$, but in both these cases the claim is vacuously true. Aug 5 comment In calculus, which questions can the naive ask that the learned cannot answer? Maybe this question is its own answer? Aug 5 answered Find a number by the decimal part of its square root Aug 5 answered Mean and Variance of “Piecewise” Normal Distribution Aug 5 comment Consistent Set of Sentences is Consistent in Expanded Language There is no need to replace any symbols in axioms of $\mathcal L'$, is there? Aug 5 answered Ways to code two arbitrary binary strings into one without loss of information, and relevant bounds