Theorem dfnn2 9038

Description: Definition of the set of positive integers. Another name for df-inn 9037. (Contributed by Jeff Hankins, 12-Sep-2013.) (Revised by Mario Carneiro, 3-May-2014.)

Assertion

Ref	Expression
dfnn2	|- NN = |^| { x | ( 1 e. x /\ A. y e. x ( y + 1 ) e. x ) }

Distinct variable group:   x, y

Proof of Theorem dfnn2

Step	Hyp	Ref	Expression
1		df-inn 9037	1 |- NN = |^| { x | ( 1 e. x /\ A. y e. x ( y + 1 ) e. x ) }

Syntax hints:   /\ wa 104   = wceq 1373   e. wcel 2176   {cab 2191   A.wral 2484   |^|cint 3885  (class class class)co 5944   1c1 7926   + caddc 7928   NNcn 9036

This theorem depends on definitions:  df-inn 9037

This theorem is referenced by:  peano5nni  9039  1nn  9047  peano2nn  9048  arch  9292  caucvgre  11292