Theorem po3nr 4240

Description: A partial order relation has no 3-cycle loops. (Contributed by NM, 27-Mar-1997.)

Assertion

Ref	Expression
po3nr	|- ( ( R Po A /\ ( B e. A /\ C e. A /\ D e. A ) ) -> -. ( B R C /\ C R D /\ D R B ) )

Proof of Theorem po3nr

Step	Hyp	Ref	Expression
1		po2nr 4239	. . 3 |- ( ( R Po A /\ ( B e. A /\ D e. A ) ) -> -. ( B R D /\ D R B ) )
2	1	3adantr2 1142	. 2 |- ( ( R Po A /\ ( B e. A /\ C e. A /\ D e. A ) ) -> -. ( B R D /\ D R B ) )
3		df-3an 965	. . 3 |- ( ( B R C /\ C R D /\ D R B ) <-> ( ( B R C /\ C R D ) /\ D R B ) )
4		potr 4238	. . . 4 |- ( ( R Po A /\ ( B e. A /\ C e. A /\ D e. A ) ) -> ( ( B R C /\ C R D ) -> B R D ) )
5	4	anim1d 334	. . 3 |- ( ( R Po A /\ ( B e. A /\ C e. A /\ D e. A ) ) -> ( ( ( B R C /\ C R D ) /\ D R B ) -> ( B R D /\ D R B ) ) )
6	3, 5	syl5bi 151	. 2 |- ( ( R Po A /\ ( B e. A /\ C e. A /\ D e. A ) ) -> ( ( B R C /\ C R D /\ D R B ) -> ( B R D /\ D R B ) ) )
7	2, 6	mtod 653	1 |- ( ( R Po A /\ ( B e. A /\ C e. A /\ D e. A ) ) -> -. ( B R C /\ C R D /\ D R B ) )

Syntax hints:   -. wn 3   -> wi 4   /\ wa 103   /\ w3a 963   e. wcel 1481   class class class wbr 3937   Po wpo 4224

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-in1 604  ax-in2 605  ax-io 699  ax-5 1424  ax-7 1425  ax-gen 1426  ax-ie1 1470  ax-ie2 1471  ax-8 1483  ax-10 1484  ax-11 1485  ax-i12 1486  ax-bndl 1487  ax-4 1488  ax-17 1507  ax-i9 1511  ax-ial 1515  ax-i5r 1516  ax-ext 2122

This theorem depends on definitions:  df-bi 116  df-3an 965  df-tru 1335  df-nf 1438  df-sb 1737  df-clab 2127  df-cleq 2133  df-clel 2136  df-nfc 2271  df-ral 2422  df-v 2691  df-un 3080  df-sn 3538  df-pr 3539  df-op 3541  df-br 3938  df-po 4226

This theorem is referenced by:  so3nr  4252