3,605 reputation
831
bio website nullteilerfrei.de
location Germany
age 29
visits member for 3 years, 2 months
seen yesterday

I'm a PhD student with research interests in Algebraic Geometry, Algebraic Complexity Theory and Geometric Invariant Theory.


Apr
8
answered Minimum Cut algorithm on undirected graph with no source or sink
Apr
8
reviewed Approve suggested edit on Associated prime ideals of Hom (Bruns and Herzog, exercise 1.2.27)
Apr
8
comment Do rational functions separate points?
@Cantlog: That's really great and a clear, elegant proof at that. Why don't you post it as an answer, I'd accept in a heartbeat.
Apr
7
reviewed Approve suggested edit on Why is $-\Delta+1$ an isomorphism between Sobolev space $W^{2,p}$ and $L^p\,$?
Apr
7
comment Do rational functions separate points?
@AsalBeagDubh: Well. I wanted to avoid it, but if you have a solution for quasi-projective $X$, I'd be curious, too.
Apr
7
asked Do rational functions separate points?
Apr
6
comment How to determine the local ring
It means localization in the multiplicative set $\{ x^k \mid k\in\mathbb N\}$. It is sometimes referred to as localization in $x$. It means adjoining $x^{-1}$, basically. Also, don't worry about questions ;).
Apr
6
comment How to determine the local ring
Yes, that is what I mean.
Apr
5
reviewed Approve suggested edit on Find all real numbers $x$ for which $\frac{8^x+27^x}{12^x+18^x}=\frac76$
Apr
5
reviewed Approve suggested edit on Groups with order divisible by $d$ and no element of order $d$
Apr
5
reviewed Approve suggested edit on A group of order $66$ has an element of order $33$
Apr
5
reviewed Approve suggested edit on Combination of Combinations
Apr
5
reviewed Approve suggested edit on Combination of Combinations
Apr
5
answered Intersection Multiplicity and Multiplicity of Zeros in Polynomial
Apr
5
comment How to determine the local ring
In larger generality, when $X$ is normal and $Z\subseteq X$ is of codimension greater or equal than two, then $\mathcal O(X)=\mathcal O(X\setminus Z)$. In this concrete case, it means that any regular function on $A^2\setminus\{ 0 \}$ can be extended to a polynomial on $A^2$. Indeed, interpret that function as a rational function $f/g$ - there is no way that $g$ only vanishes at a single point, it would have to vanish at a codimension one subvariety. Hence, the function must be a polynomial.
Apr
5
reviewed Approve suggested edit on Arranging indistinguishable objects in a circle
Apr
5
revised How to determine the local ring
deleted 101 characters in body
Apr
5
awarded  Vox Populi
Apr
5
awarded  Suffrage
Apr
5
answered How to determine the local ring