All Questions
Tagged with metric-spaces nt.number-theory
5 questions
32
votes
3
answers
2k
views
A funny metric over $\mathbb{N}$
$\DeclareMathOperator{\lcm}{lcm}$
Fiddling with numbers I realized that for positive integers $x$ and $y$, the quantity
$$\Vert x,y \Vert=\frac{\lcm(x,y)}{\gcd(x,y)}$$
has these properties:
$\Vert x,...
35
votes
6
answers
2k
views
Trigonometry / Euclidean Geometry for natural numbers?
Let $d(a,b) = 1 - \frac{2\gcd(a,b)^3}{ab(a+b)}$ be a metric on natural numbers without $0$.
The metric space $X = \{x_0,x_1,\cdots,x_n\},n>2$ is isometric embeddable in $\mathbb{R}^n$ if and only ...
24
votes
4
answers
2k
views
A reinterpretation of the $abc$ - conjecture in terms of metric spaces?
I hope it is appropriate to ask this question here:
One formulation of the abc-conjecture is
$$ c < \text{rad}(abc)^2$$
where $\gcd(a,b)=1$ and $c=a+b$. This is equivalent to ($a,b$ being ...
10
votes
0
answers
793
views
Two questions around the $abc$-conjecture
Let $d(a,b) = 1-\frac{2 \gcd(a,b)}{a+b}$, $d_{ABC}(a,b) = 1-\frac{2\gcd(a,b)^3}{ab(a+b)}$ be two metrics on natural numbers.
The abc-conjecture can be formulated using these two metrics as:
For ...
5
votes
1
answer
337
views
Greedy simplices in an ultrametric space (generalized Bhargava $p$-orderings)
Let $\left(U, d\right)$ be a finite ultrametric space -- that is, $U$ is a finite set, and $d : U \times U \to \mathbb{R}_{\geq 0}$ is a metric on $U$ such that every $x, y, z \in U$ satisfy $d\left(x,...