Thomas Drakengren, Peter Jonsson
This paper continues Nebel and Biirckert’s investigation of Allen’s interval algebra by presenting nine more maximal tractable subclasses of the algebra, in addition to their previously reported ORD-Horn subclass. Furthermore, twelve tractable subclasses are identified, whose maximality is not decided. Four of these can express the notion of sequentiality between intervals, which is not possible in the ORD-Horn algebra. The satisfiability algorithm, which is common for all the algebras, is shown to be linear.