Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Harmonic models and spanning forests of residually finite groups   We prove a number of identities relating the sofic entropy of a certain class
of non-expansive algebraic dynamical systems, the sofic entropy of the Wired
Spanning Forest and the tree entropy of Cayley graphs of residually finite
groups. We also show that homoclinic points and periodic points in harmonic
models are dense under general conditions.

8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
16
The categories of this paper are: stat
19
The categories of this paper are: eess