Computable torsion abelian groups

• Main Authors: Melnikov, Alexander G., Ng, Keng Meng
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2020
• Subjects: Science::Mathematics; Abelian Groups; Computable Structures
• Online Access: https://hdl.handle.net/10356/137680
• Institution: Nanyang Technological University

We prove that c.c. torsion abelian groups can be described by a Π04-predicate that describes the failure of a brute-force diagonalisation attempt on such groups. We show that there is no simpler description since their index set is Π04-complete. The results can be viewed as a solution to a 60 year-o...