Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Low-density series expansions for directed percolation I: A new
  efficient algorithm with applications to the square lattice   A new algorithm for the derivation of low-density series for percolation on
directed lattices is introduced and applied to the square lattice bond and site
problems. Numerical evidence shows that the computational complexity grows
exponentially, but with a growth factor $\lambda < \protect{\sqrt[8]{2}}$,
which is much smaller than the growth factor $\lambda = \protect{\sqrt[4]{2}}$
of the previous best algorithm. For bond (site) percolation on the directed
square lattice the series has been extended to order 171 (158). Analysis of the
series yields sharper estimates of the critical points and exponents.

11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
29
The categories of this paper are: funct-an