Theorem undm 1685

Description: DeMorgan's law for union. Theorem 5.2(13) of [Stoll] p. 19.

Assertion

Ref	Expression
undm	|- (V \ (A u. B)) = ((V \ A) i^i (V \ B))

Proof of Theorem undm

Step	Hyp	Ref	Expression
1		difundi 1681	1 |- (V \ (A u. B)) = ((V \ A) i^i (V \ B))

Syntax hints:   = wceq 1091  Vcvv 1348   \ cdif 1484   u. cun 1485   i^i cin 1486

This theorem is referenced by:  difun1 1687

This theorem was proved from axioms:  ax-1 3  ax-2 4  ax-3 5  ax-mp 6  ax-4 673  ax-5 674  ax-6 675  ax-7 676  ax-gen 677  ax-8 798  ax-9 799  ax-10 800  ax-11 801  ax-12 802  ax-16 922  ax-17 925  ax-ext 1074

This theorem depends on definitions:  df-bi 128  df-or 197  df-an 198  df-ex 679  df-sb 853  df-clab 1093  df-cleq 1097  df-clel 1099  df-v 1349  df-dif 1489  df-un 1490  df-in 1491

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