Theorem nnssre 8988

Description: The positive integers are a subset of the reals. (Contributed by NM, 10-Jan-1997.) (Revised by Mario Carneiro, 16-Jun-2013.)

Assertion

Ref	Expression
nnssre	|- NN C_ RR

Proof of Theorem nnssre

Step	Hyp	Ref	Expression
1		1re 8020	. 2 |- 1 e. RR
2		peano2re 8157	. . 3 |- ( x e. RR -> ( x + 1 ) e. RR )
3	2	rgen 2547	. 2 |- A. x e. RR ( x + 1 ) e. RR
4		peano5nni 8987	. 2 |- ( ( 1 e. RR /\ A. x e. RR ( x + 1 ) e. RR ) -> NN C_ RR )
5	1, 3, 4	mp2an 426	1 |- NN C_ RR

Syntax hints:   e. wcel 2164   A.wral 2472   C_ wss 3154  (class class class)co 5919   RRcr 7873   1c1 7875   + caddc 7877   NNcn 8984

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 710  ax-5 1458  ax-7 1459  ax-gen 1460  ax-ie1 1504  ax-ie2 1505  ax-8 1515  ax-10 1516  ax-11 1517  ax-i12 1518  ax-bndl 1520  ax-4 1521  ax-17 1537  ax-i9 1541  ax-ial 1545  ax-i5r 1546  ax-ext 2175  ax-sep 4148  ax-cnex 7965  ax-resscn 7966  ax-1re 7968  ax-addrcl 7971

This theorem depends on definitions:  df-bi 117  df-tru 1367  df-nf 1472  df-sb 1774  df-clab 2180  df-cleq 2186  df-clel 2189  df-nfc 2325  df-ral 2477  df-v 2762  df-in 3160  df-ss 3167  df-int 3872  df-inn 8985

This theorem is referenced by:  nnsscn  8989  nnre  8991  nnred  8997  nn0ssre  9247  nninfdclemp1  12610  nninfdclemf1  12612