Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A null model for Dunbar's circles   An individual's social group may be represented by their ego-network, formed
by the links between the individual and their acquaintances. Ego-networks
present an internal structure of increasingly large nested layers (or circles)
of decreasing relationship intensity, whose size exhibits a precise scaling
ratio. Starting from the notion of limited social bandwidth, and assuming fixed
costs for the links in each layer, we propose a null model built on a
grand-canonical ensemble that generates the observed hierarchical social
structure. The observed internal structure of ego-networks becomes a natural
outcome to expect when we assume the existence of layers demanding different
amounts of resources. In the thermodynamic limit, reached when the number of
ego-network copies is large, the specific layer degrees follow a Poisson
distribution. We also find that, under certain conditions, equispaced layer
costs are necessary to obtain a constant group size scaling. Our model presents
interesting analogies to a Bose-Einstein gas, that we briefly discuss. Finally,
we fit and compare the model with an empirical social network.

37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int