Consider a generic triangle in the upper half of the complex plane with one side on the real line. This paper presents a tailored construction of a discrete random walk whose continuum limit is a Brownian motion in the triangle, reflected instantaneously on the left and right sides with constant...

We investigate the scope for cooperation in a community engaged in repeated interactions. Players seek the help of others and approach them sequentially according to some fixed order. This defines a ranking profile: a list for each player describing the order in which he approaches other players...