Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Planck-scale physics: facts and beliefs   The relevance of the Planck scale to a theory of quantum gravity has become a
worryingly little examined assumption that goes unchallenged in the majority of
research in this area. However, in all scientific honesty, the significance of
Planck's natural units in a future physical theory of spacetime is only a
plausible, yet by no means certain, assumption. The purpose of this article is
to clearly separate fact from belief in this connection.

35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga