Theorem rel0 4900

Description: The empty set is a relation. (Contributed by NM, 26-Apr-1998.)

Assertion

Ref	Expression
rel0	|- Rel (/)

Proof of Theorem rel0

Step	Hyp	Ref	Expression
1		0ss 3561	. 2 |- (/) C_ ( _V X. _V )
2		df-rel 4779	. 2 |- ( Rel (/) <-> (/) C_ ( _V X. _V ) )
3	1, 2	mpbir 146	1 |- Rel (/)

Syntax hints:   _Vcvv 2821   C_ wss 3220   (/)c0 3520   X. cxp 4770   Rel wrel 4777

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 623  ax-in2 624  ax-io 721  ax-5 1500  ax-7 1501  ax-gen 1502  ax-ie1 1546  ax-ie2 1547  ax-8 1557  ax-10 1558  ax-11 1559  ax-i12 1560  ax-bndl 1562  ax-4 1563  ax-17 1579  ax-i9 1583  ax-ial 1587  ax-i5r 1588  ax-ext 2220

This theorem depends on definitions:  df-bi 117  df-tru 1405  df-nf 1514  df-sb 1816  df-clab 2225  df-cleq 2231  df-clel 2234  df-nfc 2381  df-v 2823  df-dif 3222  df-in 3226  df-ss 3233  df-nul 3521  df-rel 4779

This theorem is referenced by:  reldm0  4997  cnv0  5189  cnveq0  5242  co02  5299  co01  5300  tpos0  6538  0er  6834