Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Comment on "Superhard Semiconducting Optically Transparent High Pressure
  Phase of Boron"   This Comment points out a number of errors in the recent paper by Zarechnaya,
Dubrovinskaia, Dubrovinsky, et al. (Phys. Rev. Lett. 102, 185501 (2009)).
Results and conclusions presented by Zarechnaya et al. (2009) are either
incorrect or have been presented before.

29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom