Friedberg numbering

In computability theory, a Friedberg numbering is a numbering (enumeration) of the set of all uniformly recursively enumerable sets that has no repetitions: each recursively enumerable set appears exactly once in the enumeration (Vereščagin and Shen 2003:30).

The existence of such numberings was established by Richard M. Friedberg in 1958 (Cutland 1980:78).