8,479 reputation
11941
bio website cube.fredrikmeyer.net
location Oslo, Norway
age 25
visits member for 3 years, 9 months
seen yesterday

I'm a PhD Student at the University of Oslo, studying algebraic geometry. Emphasis on combinatorial aspects, like Stanley-Reisner rings and deformations.


1d
comment Thinking About Fractional Ideals Geometrically
Fractional ideals of $\mathbb Z$ correspond to line bundles (or invertible sheaves, or locally free sheaves of rank $1$) on $\mathrm{Spec} \mathbb Z$.
Aug
25
awarded  Notable Question
Aug
17
comment Geometrical description of maps of schemes
A map from $Spec \mathbb C[z]/z^2$ to $\mathbb A^2$ correspond to a tangent vector of the latter.
Aug
16
comment Looking for a smooth curve that is not rational
The intersection of two quadrics in $\mathbb P^3$ is an elliptic curve.
Aug
11
comment I need help to understand blowups of points in curves in $\mathbb A^2$
@user42912 That is correct. I recommend Chapter I, section 4 of Hartshorne's book. It is a very concise introduction to blowups in the end of the section, giving the equations.
Aug
10
revised Going Down Theorem, AM
added 90 characters in body
Aug
10
revised I need help to understand blowups of points in curves in $\mathbb A^2$
added 479 characters in body
Aug
10
answered I need help to understand blowups of points in curves in $\mathbb A^2$
Aug
6
awarded  Enlightened
Aug
6
awarded  Good Answer
Aug
6
awarded  Nice Answer
Aug
2
comment Extension of the field of scalars.
@HansGiebenrath Thank you for the comment. I've removed my flawed example.
Aug
2
revised Extension of the field of scalars.
added 7 characters in body
Jul
20
comment Why do only fixed points contribute to the Euler characteristic?
An algebraic scheme is usally defined as a scheme of finite type.
Jul
10
awarded  Good Question
Jul
2
awarded  Curious
Jun
28
comment on the coordinate ring of $\mathbb{A}^n \times \mathbb{P}^{m}$
@MarianoSuárez-Alvarez Ops, I meant subvarieties, not functions.
Jun
28
revised on the coordinate ring of $\mathbb{A}^n \times \mathbb{P}^{m}$
added 165 characters in body
Jun
27
answered on the coordinate ring of $\mathbb{A}^n \times \mathbb{P}^{m}$
Jun
25
answered How to show if n is prime, then $\{1,2,…,n-1\}$ is a group?