Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The absence of the Efimov effect in systems of one- and two-dimensional
  particles   We study virtual levels of $N$-particle Schr\"odinger operators and prove
that if the particles are one-dimensional and $N\ge 3$, then virtual levels at
the bottom of the essential spectrum correspond to eigenvalues. The same is
true for two-dimensional particles if $N\ge 4$. These results are applied to
prove the non-existence of the Efimov effect in systems of $N\ge 4$
one-dimensional or $N\ge 5$ two-dimensional particles.

1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
16
The categories of this paper are: stat