Pseudo-orbit

Roughly speaking, an

-pseudo orbit is obtained by successively following the system, each time making an "error" of size less than

Definition: A sequence of points in satisfying

is called an -pseudo-orbit of length .

Note that the definition of a real orbit can be written in an analogous way as follows. An orbit of length is a sequence such that

Although Conley [3] uses the term " -chain" for an -pseudo-orbit, the latter terminology is more descriptive for the applications presented here and will be used throughout this paper.