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Syntax Definition cab 2339
Description: Introduce the class builder or class abstraction notation ("the class of sets x such that φ is true"). Our class variables A, B, etc. range over class builders (implicitly in the case of defined class terms such as df-nul 3551). Note that a setvar variable can be expressed as a class builder per theorem cvjust 2348, justifying the assignment of setvar variables to class variables via the use of cv 1641.
Ref Expression
wph wff φ
vx setvar x
Ref Expression
cab class {x φ}

See definition df-clab 2340 for more information.

Colors of variables: wff setvar class
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