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Definition df-nul 4051
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 4052. (Contributed by NM, 17-Jun-1993.)
Assertion
Ref Expression
df-nul ∅ = (V ∖ V)

Detailed syntax breakdown of Definition df-nul
StepHypRef Expression
1 c0 4050 . 2 class
2 cvv 3332 . . 3 class V
32, 2cdif 3704 . 2 class (V ∖ V)
41, 3wceq 1624 1 wff ∅ = (V ∖ V)
Colors of variables: wff setvar class
This definition is referenced by:  dfnul2  4052  noel  4054
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