df-nul - New Foundations Explorer

	New Foundations Explorer		< Previous Next > Nearby theorems
Mirrors > Home > NFE Home > Th. List > df-nul		GIF version

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**
Step	Hyp	Ref	Expression
1		c0 3550	. 2 class ∅
2		cvv 2859	. . 3 class V
3	2, 2	cdif 3206	. 2 class (V ∖ V)
4	1, 3	wceq 1642	1 wff ∅ = (V ∖ V)

Colors of variables: wff setvar class

This definition is referenced by: dfnul2 3552 noel 3554 complV 4070

W3C validator