Theorem so0 4423

Description: Any relation is a strict ordering of the empty set. (Contributed by NM, 16-Mar-1997.) (Proof shortened by Andrew Salmon, 25-Jul-2011.)

Assertion

Ref	Expression
so0	|- R Or (/)

Proof of Theorem so0

Dummy variables x y z are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		po0 4408	. 2 |- R Po (/)
2		ral0 3596	. 2 |- A. x e. (/) A. y e. (/) A. z e. (/) ( x R y -> ( x R z \/ z R y ) )
3		df-iso 4394	. 2 |- ( R Or (/) <-> ( R Po (/) /\ A. x e. (/) A. y e. (/) A. z e. (/) ( x R y -> ( x R z \/ z R y ) ) ) )
4	1, 2, 3	mpbir2an 950	1 |- R Or (/)

Syntax hints:   -> wi 4   \/ wo 715   A.wral 2510   (/)c0 3494   class class class wbr 4088   Po wpo 4391   Or wor 4392

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-in1 619  ax-in2 620  ax-io 716  ax-5 1495  ax-7 1496  ax-gen 1497  ax-ie1 1541  ax-ie2 1542  ax-8 1552  ax-10 1553  ax-11 1554  ax-i12 1555  ax-bndl 1557  ax-4 1558  ax-17 1574  ax-i9 1578  ax-ial 1582  ax-i5r 1583  ax-ext 2213

This theorem depends on definitions:  df-bi 117  df-tru 1400  df-nf 1509  df-sb 1811  df-clab 2218  df-cleq 2224  df-clel 2227  df-nfc 2363  df-ral 2515  df-v 2804  df-dif 3202  df-nul 3495  df-po 4393  df-iso 4394

This theorem is referenced by: (None)