Automorphisms of the lattice of recursively enumerable sets

Robert I. Soare
1974 Bulletin of the American Mathematical Society  
Let S denote the lattice of recursively enumerable (r.e.) sets under inclusion, and let #* denote the quotient lattice of S modulo the ideal 3F of finite sets. For A e ê let A* denote the equivalence class in <ƒ* which contains A. An r.e. set A is maximal if A* is a coatom (maximal element) of (A)=B (0(^4*)= 5*). A permutation p of N induces an automorphism O of S {$*) if AMS (MOS) subject classifications (1970). Primary 02F25; Secondary 02F30. Key words and phrases. Maximal set* Post problem,
more » ... igh degree, low degree, lattice of r.e. sets. 1 The author owes much to the following who have supplied corrections, suggestions and information on this topic,
doi:10.1090/s0002-9904-1974-13350-1 fatcat:uyrxbaijizc5pektmahv3qkn6u