I am having a hard time to follow a concept from Introduction to the theory of computation (3rd ed.) by Michael Sipser. I got confused by the last sentence. Ok, we can convert regular express into finite automata and vice versa. Does "Recall that a regular language is one that is recognized by some finite automaton." mean we can use more than one finite automata to describe one singular regular expression? if so, can we use more than one regular expresses to describe one singular finite automaton? If not, what does the last sentence really mean?
Content from the book On page 66
Regular expressions and finite automata are equivalent in their descriptive power. This fact is surprising because finite automata and regular expressions superficially appear to be rather different. However, any regular expression can be converted into a finite automaton that recognizes the language it describes, and vice versa. Recall that a regular language is one that is recognized by some finite automaton.