Information in Strings: Enumeration of Eulerian Paths and Eulerian Components in Markov Sequences

In this paper, we evaluate the number of Eulerian circuits that can be obtained by an arbitrary rotation in a Markovian string, i.e., corresponding to a given Markovian type. Since all rotations do not result in an Eulerian circuit, but several of them, called Eulerian components; we also investigate the number of Eulerian components that result from a random rotation in a Markovian string. We consider the asymptotic behaviour of those quantities when the size of the string n tends to infinity. In particular we show that the average number of components tends to be in log V , where V is the size of a large alphabet, in the uniform case.