Recursively enumerable degrees and the conjugacy problem
Donald J. Collins · Acta Mathematica · 1969
The principal result obtained is the theorem that for every recursively enumerable degree of unsolvability, there exists a finitely presented group whese conjugacy problem has that degree.(Parts I, II, III and IV.)In Part V this result is generalised to the theorem that certain complexes of recursively enumerable degrees of unsolvability may be obtained as the degrees of a complex of problems concerning conjugacy in a finitely presented group.It is a pleasure to acknowledge the encouragement and inspiration provided by Professor William Boone during this work.