Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Constructing H\"older maps to Carnot groups   In this paper, we construct H\"older maps to Carnot groups equipped with a
Carnot metric, especially the first Heisenberg group $\mathbb{H}$. Pansu and
Gromov observed that any surface embedded in $\mathbb{H}$ has Hausdorff
dimension at least 3, so there is no $\alpha$-H\"older embedding of a surface
into $\mathbb{H}$ when $\alpha>\frac{2}{3}$. Z\"ust improved this result to
show that when $\alpha>\frac{2}{3}$, any $\alpha$-H\"older map from a
simply-connected Riemannian manifold to $\mathbb{H}$ factors through a metric
tree. In the present paper, we show that Z\"ust's result is sharp by
constructing $(\frac{2}{3}-\epsilon)$-H\"older maps from $D^2$ and $D^3$ to
$\mathbb{H}$ that do not factor through a tree. We use these to show that if
$0<\alpha < \frac{2}{3}$, then the set of $\alpha$-H\"older maps from a compact
metric space to $\mathbb{H}$ is dense in the set of continuous maps and to
construct proper degree-1 maps from $\mathbb{R}^3$ to $\mathbb{H}$ with
H\"older exponents arbitrarily close to $\frac{2}{3}$.

1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
3
The categories of this paper are: physics