Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gabor orthogonal bases and convexity   Let $g(x)=\chi_B(x)$ be the indicator function of a bounded convex set in
$\Bbb R^d$, $d\geq 2$, with a smooth boundary and everywhere non-vanishing
Gaussian curvature. Using a combinatorial appraoch we prove that if $d \neq 1
\mod 4$, then there does not exist $S \subset {\Bbb R}^{2d}$ such that ${
\{g(x-a)e^{2 \pi i x \cdot b} \}}_{(a,b) \in S}$ is an orthonormal basis for
$L^2({\Bbb R}^d)$.

24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
18
The categories of this paper are: econ