Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Comment on "History Effects and Phase Diagram near the Lower Critical
  Point in YBa_2Cu_3O_{7-\delta} Single Crystals"   This is a Comment on an experimental paper by Zhukov et al. on the issue of a
lower critical point, seen only in YBCO clean samples, of the first order
transition line implying a vortex liquid-freezing. An explanation with a firm
theoretical basis of the strange doping dependence of the lower critical point
is presented.

27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an