I thank my supervisor Anna Eklöf for letting me continue with her dimensionality and intervality projects. I also thank Alyssa Cirtwill and György Barabas for both useful discussions and help with the manuscript. Likewise, I am also grateful to my fellow students Isabelle Norström and Inger-Marie Wohlfarth. Special thanks go to the National Supercomputer Centre at Linköping University for the use of their facility with the intervality calculations.