Theorem add42i 8085

Description: Rearrangement of 4 terms in a sum. (Contributed by NM, 22-Aug-1999.)

Hypotheses

Ref	Expression
add.1	|- A e. CC
add.2	|- B e. CC
add.3	|- C e. CC
add4.4	|- D e. CC

Assertion

Ref	Expression
add42i	|- ( ( A + B ) + ( C + D ) ) = ( ( A + C ) + ( D + B ) )

Proof of Theorem add42i

Step	Hyp	Ref	Expression
1		add.1	. . 3 |- A e. CC
2		add.2	. . 3 |- B e. CC
3		add.3	. . 3 |- C e. CC
4		add4.4	. . 3 |- D e. CC
5	1, 2, 3, 4	add4i 8084	. 2 |- ( ( A + B ) + ( C + D ) ) = ( ( A + C ) + ( B + D ) )
6	2, 4	addcomi 8063	. . 3 |- ( B + D ) = ( D + B )
7	6	oveq2i 5864	. 2 |- ( ( A + C ) + ( B + D ) ) = ( ( A + C ) + ( D + B ) )
8	5, 7	eqtri 2191	1 |- ( ( A + B ) + ( C + D ) ) = ( ( A + C ) + ( D + B ) )

Syntax hints:   = wceq 1348   e. wcel 2141  (class class class)co 5853   CCcc 7772   + caddc 7777

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-io 704  ax-5 1440  ax-7 1441  ax-gen 1442  ax-ie1 1486  ax-ie2 1487  ax-8 1497  ax-10 1498  ax-11 1499  ax-i12 1500  ax-bndl 1502  ax-4 1503  ax-17 1519  ax-i9 1523  ax-ial 1527  ax-i5r 1528  ax-ext 2152  ax-addcl 7870  ax-addcom 7874  ax-addass 7876

This theorem depends on definitions:  df-bi 116  df-3an 975  df-tru 1351  df-nf 1454  df-sb 1756  df-clab 2157  df-cleq 2163  df-clel 2166  df-nfc 2301  df-rex 2454  df-v 2732  df-un 3125  df-sn 3589  df-pr 3590  df-op 3592  df-uni 3797  df-br 3990  df-iota 5160  df-fv 5206  df-ov 5856

This theorem is referenced by: (None)