@Inproceedings{EPTCS77.3, author = {Aceto, Luca and Ing\'olfsd\'ottir, Anna}, year = {2012}, title = {Characteristic Formulae for Relations with Nested Fixed Points}, editor = {Miller, Dale and \'Esik, Zolt\'an}, booktitle = {{\rm Proceedings 8th Workshop on} Fixed Points in Computer Science, {\rm Tallinn, Estonia, 24th March 2012}}, series = {Electronic Proceedings in Theoretical Computer Science}, volume = {77}, publisher = {Open Publishing Association}, pages = {15-22}, doi = {10.4204/EPTCS.77.3}, }