In computability theory, a Friedberg numbering is a computable numbering (enumeration) of the set of all computably enumerable sets that has no repetitions: each computably 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).
References Nigel Cutland (1980), Computability: An Introduction to Recursive Function Theory, Cambridge University Press. ISBN 9780521294652. Richard M. Friedberg (1958), Three Theorems on Recursive Enumeration. I. Decomposition. II. Maximal Set. III. Enumeration Without Duplication, Journal of Symbolic Logic 23:3, pp. 309–316. Nikolaj K. Vereščagin and A. Shen (2003), Computable Functions, American Mathematical Soc.
External links Institute of Mathematics