Logic in Computer Science, Symposium on (2010)
Edinburgh, United Kingdom
July 11, 2010 to July 14, 2010
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/LICS.2010.10
Several new undecidability results on isomorphism problems for automatic structures are shown: (i) The isomorphism problem for automatic equivalence relations is \pi^0_1-complete. (ii) The isomorphism problem for automatic trees of height $n$ ≳ 2 is \pi^0_2$n$–3-complete. (iii) The isomorphism problem for automatic linear orders is not arithmetical.
automatic structures, isomorphism problems, arithmetical hierarchy
J. Liu, D. Kuske and M. Lohrey, "The Isomorphism Problem on Classes of Automatic Structures," Logic in Computer Science, Symposium on(LICS), Edinburgh, United Kingdom, 2010, pp. 160-169.