ABSTRACT
The mathematical theory of chaos has known a lot of developments since the first occurrence of this term in 1975 [92], one of the most known being the definition of chaos given by Robert L. Devaney [61]. The goal of this chapter is to introduce his definition, whereas other definitions will be given in the next chapter. The reader who wants to go deeper into the topic is referred to
Machines
the book by Devaney [61], and to the theses of Enrico Formenti [66], [67] and Sylvie Ruette [123].
