1. A computer-implemented method of analyzing messages in a computer system to allow workflows constituted by the messages to be identified, the method comprising: analyzing a sequence of messages in a computer system in order to classify the messages, thereby producing a corresponding sequence of classifications of the messages; and, applying sequence induction to the sequence of classifications of the messages to produce (i) a set of sub-sequences of the classifications of the messages and (ii) a sequence grammar for the sub-sequences, from which a workflow constituted by the sequence of messages can be identified, wherein the set of sub-sequences of the classifications of the messages and the sequence grammar for the sub-sequences are obtained by building rules that describe bigrams formed between classifications of the messages in the sequence of classifications of the messages; and wherein a choice to build a new rule is based on all the bigrams that can be formed given the most recent classification in the input sequence of classifications of the messages and each of the classifications in the sequence of classifications of the messages falling within a window.