Skip to main content

All Questions

Filter by
Sorted by
Tagged with
28 votes
6 answers
2k views

Patterns among integer-distance points

Mark each point of $\mathbb{N}^2$ ($\mathbb{N}$ the natural numbers) if its Euclidean distance from the origin is an integer. One obtains a plot like this, symmetric about the $45^\circ$ diagonal. ...
Joseph O'Rourke's user avatar
13 votes
1 answer
1k views

Rational points on surfaces of general type

The weak Lang conjecture asserts that rational points on a variety of general type defined over $\mathbb{Q}$ are not Zariski dense (same replacing $\mathbb{Q}$ with a number field). This one is proved ...
Jérémy Blanc's user avatar
11 votes
5 answers
4k views

How much do I need to learn algebraic geometry to understand arithmetics over number fields

I am at the stage of learning. Mostly, I am attracted by algebraic number theory. Roughly speaking, I am interested in the rational points of algebraic varieties. I am little bit afraid to start to ...
Ofra's user avatar
  • 1,613
7 votes
1 answer
218 views

Subfields of Hilbertian fields

This question is about the Remark on the top of page 22 of Serre's Topics in Galois Theory, available here : http://www.ms.uky.edu/~sohum/ma561/notes/workspace/books/serre_galois_theory.pdf My ...
Harry's user avatar
  • 353
5 votes
1 answer
717 views

rational points of a hyperelliptic curve of genus 3

Let $K=\mathbb{Q}(\sqrt{-1}).$ I have the following hyperelliptic curve of genus 3: $$ C : y^2 = (x^2-x+1)(x^6+x^5-6x^4 -3x^3+14x^2-7x+1) $$ I want to find $C(K)$. My first attempt was to compute the ...
bijection123's user avatar
3 votes
1 answer
395 views

Finding $K$-rational points on $X_0(35)$

Let $K=\mathbb{Q}(\sqrt{-2})$. How can I compute the $K$-rational points on the modular curve $X_0(35)$? Recall that $X_0(35)$ is a hyperelliptic curve of genus 3 and has the simplified affine model: \...
5W1H's user avatar
  • 31
2 votes
1 answer
600 views

Density of rational points over finite fields, an estimate of Lang-Weil constant

Let $X\hookrightarrow\mathbb P^n_{\mathbb F_q}$ be a geometrically integral hypersurface over the finite field $\mathbb F_q$ of degree $\delta$. In order to estimate the number of its rational points, ...
var's user avatar
  • 403
2 votes
0 answers
198 views

Finding rational points via birational map

Let $C$ be an affine curve given by $p_C(x,y)=0$ where $$ p_C=2x^3y + 2xy^3 +x^3 + y^3 + 5x^2y + 5xy^2 + 2x^2 + 2y^2 + 2x^2y^2 + 2xy $$ and let $\overline{C}$ denote the projective closure of $C$. For ...
monoid911's user avatar
1 vote
2 answers
203 views

Counting number of $2\times 2$ unimodular matrices of particular type

From set of numbers from $\Bbb S=\{0,1,\dots,m\}$, how many distinct $3\times 3$ unimodular matrices parametrized by $(a,b,c,d,e,f)\in\Bbb S^6$ of following type can one form? \begin{bmatrix} a^2 &...
user avatar
1 vote
0 answers
122 views

Rational points on an elliptic curve the denominator of x is a square

Let $f \in \mathbb Q[x]$ be a squarefree cubic polynomial with nonzero constant coefficient and consider the elliptic curve $E : y^2 = f(x)$. Define $E(\mathbb Q)' \subseteq E(\mathbb Q)$ as $$\left \...
Maarten Derickx's user avatar
0 votes
0 answers
87 views

Computational tool for checking the existence of non-trivial rational zero of a cubic form

Suppose we consider a arbitrary cubic homogeneous form $f$ in in four or five variables over the rational field. Is there any computational tool or algorithm to check whether this cubic homogeneous ...
Sky's user avatar
  • 923