Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Order of the phase transition in models of DNA thermal denaturation   We examine the behavior of a model which describes the melting of
double-stranded DNA chains. The model, with displacement-dependent stiffness
constants and a Morse on-site potential, is analyzed numerically; depending on
the stiffness parameter, it is shown to have either (i) a second-order
transition with "nu_perpendicular" = - beta = 1, "nu_parallel" = gamma/2 = 2
(characteristic of short range attractive part of the Morse potential) or (ii)
a first-order transition with finite melting entropy, discontinuous fraction of
bound pairs, divergent correlation lengths, and critical exponents
"nu_perpendicular" = - beta = 1/2, "nu_parallel" = gamma/2 = 1.

1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
18
The categories of this paper are: econ