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Mirrors > Home > MPE Home > Th. List > cab | Structured version Visualization version GIF version |
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 3898). Note that a setvar variable can be expressed as a class builder per theorem cvjust 2616, justifying the assignment of setvar variables to class variables via the use of cv 1479. |
Ref | Expression |
---|---|
wph | wff 𝜑 |
vx | setvar 𝑥 |
Ref | Expression |
---|---|
cab | class {𝑥 ∣ 𝜑} |
Colors of variables: wff setvar class |
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