Weakly maximal decidable structures

We prove that there exists a structure M whose monadic second order theory is decidable, and such that the elementary theory of every expansion of M by a constant is undecidable. 1991 Mathematics Subject Classification. 03B25, 03C57, 03D05.

• Type: Journal
• Year: 2008
• Where: ITA
• Authors: Alexis Bès, Patrick Cégielski
• Keywords: Communications, ITA 2008, Mathematics Subject Classification, Order Theory