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Is this known alternating sum for Euler's constant? 27 Aug 2013 | 04:45 pm
This probably is known, but Wolfram Alpha doesn't recognize it and couldn't find it in Mathworld (there is something close, but using floor). We have $\lim_{s \to 1} (\zeta(s)-1/(s-1)) = \gamma$ Als...
Morphisms of Neron models 27 Aug 2013 | 04:34 pm
Let $S$ be a connected Dedekind scheme with field of fractions $K$. Let $A_K$ and $B_K$ be abelian varieties over $K$, and let $A$ and $B$ be the Neron models over $S$ of $A_K$ and $B_K$ respectively....
Trick for integral involving normal distribution 27 Aug 2013 | 03:10 pm
I want to obtain the integral: $$\int_{{\mathbb R}^n} \frac{1}{(2\pi)^{\frac{n}{2}}\vert\Sigma\vert^{\frac{1}{2}}}\exp\left[-\frac{1}{2}({\bf y} - {\bf X}{\beta})^{\top} \Sigma^{-1}({\bf y} - {\bf X}...
Artinian rings where all injective hulls of simple modules have finite length 27 Aug 2013 | 02:23 pm
Let $A$ be a unitary artinian ring. Suppose additionally that the injective hulls of all simple modules have finite length (or, equivalently, are finitely generated). Does the ring $A$ have to posses...
A class of rings related to rings with IBN property 27 Aug 2013 | 02:04 pm
A ring $R$ (with 1) has IBN property if free $R$-modules have unique rank. In the same fashion, lets call $R$ a good ring if in every free $R$-module any independent set can be extended to a basis. I ...
There are only finitely many varieties up to deformation 27 Aug 2013 | 01:01 pm
Let $h$ be a polynomial. Then results of several authors (including Matsusaka, Mumford, Kollar and Viehweg) imply that the moduli space of polarized varieties with Hilbert polynomial $h$ is of finite ...
Properties of sequence of general elements 27 Aug 2013 | 11:48 am
Let $I=(a_1,\ldots,a_n)$ and write $x_i=\sum_{j=1}^{n}{\lambda_{ij}}{a_j}$ for $1\leq i\leq s$ and $(\lambda_{ij})\in R^{sn}$. The elements $x_1,\ldots,x_s$ form a sequence of general elements in $I$ ...
Find all the isomorphisms between two planar graphs 27 Aug 2013 | 11:03 am
Since planar graph isomorphic problem can be solved in polynomial, can we find all isomorphisms between two planar graphs in polynomial time?
What are the binary products in the partial morphism categories? [on hold] 27 Aug 2013 | 10:25 am
In partial morphism category of $Set$ binary product of $A$ and $B$ is $A\coprod B\coprod A\times B$. What is it in an arbitrary category? It would be so kind of you if you could help me and send me t...
On tangent spaces of Steifel Manifolds 27 Aug 2013 | 10:01 am
I was trying to read Edelman et al.'s 1998 paper "The Geometry of Algorithms with Orthogonality Constraints" and since I don't have any differential geometry or much linear algebra background I am stu...
