Theorem comorr2 463

Description: Commutation law. (Contributed by NM, 26-Nov-1997.)

Assertion

Ref	Expression
comorr2	b C (a ∪ b)

Proof of Theorem comorr2

Step	Hyp	Ref	Expression
1		comor2 462	. 2 (a ∪ b) C b
2	1	comcom 453	1 b C (a ∪ b)

Syntax hints:   C wc 3   ∪ wo 6

This theorem was proved from axioms:  ax-a1 30  ax-a2 31  ax-a3 32  ax-a5 34  ax-r1 35  ax-r2 36  ax-r4 37  ax-r5 38  ax-r3 439

This theorem depends on definitions:  df-b 39  df-a 40  df-t 41  df-f 42  df-le1 130  df-le2 131  df-c1 132  df-c2 133

This theorem is referenced by:  ud3lem1c  568  u4lemanb  618  u4lemob  633  u4lemc1  683  u4lem5  764  u4lem6  768  u3lem13b  790  3vth9  812  2oath1  826