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Definition df-nul 3551
Description: Define the empty set. Special case of Exercise 4.10(o) of [Mendelson] p. 231. For a more traditional definition, but requiring a dummy variable, see dfnul2 3552. (Contributed by NM, 5-Aug-1993.)
Assertion
Ref Expression
df-nul = (V V)

Detailed syntax breakdown of Definition df-nul
StepHypRef Expression
1 c0 3550 . 2 class
2 cvv 2859 . . 3 class V
32, 2cdif 3206 . 2 class (V V)
41, 3wceq 1642 1 wff = (V V)
Colors of variables: wff setvar class
This definition is referenced by:  dfnul2  3552  noel  3554  complV  4070
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