On ergodic measures
Yael Naim Dowker, George Lederer · Proceedings of the American Mathematical Society · 1964
AÇZB' will stand for 'A is a subset of B', while 'A EB' for 'A is a proper subset of B'.The set of points p, T(p), T2(p), • • • is called the positive semiorbit of p and will be denoted by 0P.The set of limit points of the sequence p, T(p), T2(p), ■ ■ • in ß is called the co-limit set of p and will be denoted by cop.The set of points p, T(p), T~x(p), T2(p), T~2(p), • ■ • is called the orbit of p and will be denoted by 0P.The closure of the semiorbit (orbit) in ß is called the semiorbit closure (orbit closure) and will be denoted by 0P(0P).ïfl(p, p) will denote the open sphere about p of radius p.