Gödel operation

In mathematical set theory, a set of Gödel operations is a finite collection of operations on sets that can be used to construct the constructible sets from ordinals. Gödel (1940) introduced the original set of 8 Gödel operations 𝔉₁,...,𝔉₈ under the name fundamental operations. Other authors sometimes use a slightly different set of about 8 to 10 operations, usually denoted G₁, G₂,...