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Definition df-nul 3204
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 3205. (Contributed by NM, 5-Aug-1993.)
Assertion
Ref Expression
df-nul ∅ = (V ∖ V)

Detailed syntax breakdown of Definition df-nul
StepHypRef Expression
1 c0 3203 . 2 class
2 cvv 2534 . . 3 class V
32, 2cdif 2893 . 2 class (V ∖ V)
41, 3wceq 1374 1 wff ∅ = (V ∖ V)
Colors of variables: wff set class
This definition is referenced by:  dfnul2  3205  noel  3207
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