Theorem add12d 8126

Description: Commutative/associative law that swaps the first two terms in a triple sum. (Contributed by Mario Carneiro, 27-May-2016.)

Hypotheses

Ref	Expression
addd.1	⊢ (𝜑 → 𝐴 ∈ ℂ)
addd.2	⊢ (𝜑 → 𝐵 ∈ ℂ)
addd.3	⊢ (𝜑 → 𝐶 ∈ ℂ)

Assertion

Ref	Expression
add12d	⊢ (𝜑 → (𝐴 + (𝐵 + 𝐶)) = (𝐵 + (𝐴 + 𝐶)))

Proof of Theorem add12d

Step	Hyp	Ref	Expression
1		addd.1	. 2 ⊢ (𝜑 → 𝐴 ∈ ℂ)
2		addd.2	. 2 ⊢ (𝜑 → 𝐵 ∈ ℂ)
3		addd.3	. 2 ⊢ (𝜑 → 𝐶 ∈ ℂ)
4		add12 8117	. 2 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ ∧ 𝐶 ∈ ℂ) → (𝐴 + (𝐵 + 𝐶)) = (𝐵 + (𝐴 + 𝐶)))
5	1, 2, 3, 4	syl3anc 1238	1 ⊢ (𝜑 → (𝐴 + (𝐵 + 𝐶)) = (𝐵 + (𝐴 + 𝐶)))

Syntax hints:   → wi 4   = wceq 1353   ∈ wcel 2148  (class class class)co 5877  ℂcc 7811   + caddc 7816

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-io 709  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-10 1505  ax-11 1506  ax-i12 1507  ax-bndl 1509  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-ext 2159  ax-addcom 7913  ax-addass 7915

This theorem depends on definitions:  df-bi 117  df-3an 980  df-tru 1356  df-nf 1461  df-sb 1763  df-clab 2164  df-cleq 2170  df-clel 2173  df-nfc 2308  df-rex 2461  df-v 2741  df-un 3135  df-sn 3600  df-pr 3601  df-op 3603  df-uni 3812  df-br 4006  df-iota 5180  df-fv 5226  df-ov 5880

This theorem is referenced by:  subsub2  8187  bdtrilem  11249