MPE Home Metamath Proof Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  MPE Home  >  Th. List  >  df-nul Unicode version

Definition df-nul 3785
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 3786. (Contributed by NM, 17-Jun-1993.)
Assertion
Ref Expression
df-nul

Detailed syntax breakdown of Definition df-nul
StepHypRef Expression
1 c0 3784 . 2
2 cvv 3109 . . 3
32, 2cdif 3472 . 2
41, 3wceq 1395 1
Colors of variables: wff setvar class
This definition is referenced by:  dfnul2  3786  noel  3788
  Copyright terms: Public domain W3C validator