The genre system is not based on formal rules but "system presumptions". Author identified four fundamental approaches to the genre systém:
1. Metaphysical approach (the French classicism during the 17th and 18th century);
2. approach bäsed on onthology (Aristotle's theory of tragedy, Lukács' early theory of the novel);
3. model based on communicative situations (André Jolles, Mikhail Bakhtin);
4. model based on social function of literature (Ludwig Schuecking and Boris Eikhenbaum).