Theorem dfnn2 8984

Description: Definition of the set of positive integers. Another name for df-inn 8983. (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 8983	1 |- NN = |^| { x | ( 1 e. x /\ A. y e. x ( y + 1 ) e. x ) }

Syntax hints:   /\ wa 104   = wceq 1364   e. wcel 2164   {cab 2179   A.wral 2472   |^|cint 3870  (class class class)co 5918   1c1 7873   + caddc 7875   NNcn 8982

This theorem depends on definitions:  df-inn 8983

This theorem is referenced by:  peano5nni  8985  1nn  8993  peano2nn  8994  arch  9237  caucvgre  11125