Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Voluntary rewards mediate the evolution of pool punishment for
  maintaining public goods in large populations   Punishment is a popular tool when governing commons in situations where free
riders would otherwise take over. It is well known that sanctioning systems,
such as the police and courts, are costly and thus can suffer from those who
free ride on other's efforts to maintain the sanctioning systems (second-order
free riders). Previous game-theory studies showed that if populations are very
large, pool punishment rarely emerges in public good games, even when
participation is optional, because of second-order free riders. Here we show
that a matching fund for rewarding cooperation leads to the emergence of pool
punishment, despite the presence of second-order free riders. We demonstrate
that reward funds can pave the way for a transition from a population of free
riders to a population of pool punishers. A key factor in promoting the
transition is also to reward those who contribute to pool punishment, yet not
abstaining from participation. Reward funds eventually vanish in raising pool
punishment, which is sustainable by punishing the second-order free riders.
This suggests that considering the interdependence of reward and punishment may
help to better understand the origins and transitions of social norms and
institutions.

28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys