Theorem mnd12g 18707

Description: Commutative/associative law for monoids, with an explicit commutativity hypothesis. (Contributed by Mario Carneiro, 21-Apr-2016.)

Hypotheses

Ref	Expression
mndcl.b	⊢ 𝐵 = (Base‘𝐺)
mndcl.p	⊢ + = (+g‘𝐺)
mnd4g.1	⊢ (𝜑 → 𝐺 ∈ Mnd)
mnd4g.2	⊢ (𝜑 → 𝑋 ∈ 𝐵)
mnd4g.3	⊢ (𝜑 → 𝑌 ∈ 𝐵)
mnd4g.4	⊢ (𝜑 → 𝑍 ∈ 𝐵)
mnd12g.5	⊢ (𝜑 → (𝑋 + 𝑌) = (𝑌 + 𝑋))

Assertion

Ref	Expression
mnd12g	⊢ (𝜑 → (𝑋 + (𝑌 + 𝑍)) = (𝑌 + (𝑋 + 𝑍)))

Proof of Theorem mnd12g

Step	Hyp	Ref	Expression
1		mnd12g.5	. . 3 ⊢ (𝜑 → (𝑋 + 𝑌) = (𝑌 + 𝑋))
2	1	oveq1d 7435	. 2 ⊢ (𝜑 → ((𝑋 + 𝑌) + 𝑍) = ((𝑌 + 𝑋) + 𝑍))
3		mnd4g.1	. . 3 ⊢ (𝜑 → 𝐺 ∈ Mnd)
4		mnd4g.2	. . 3 ⊢ (𝜑 → 𝑋 ∈ 𝐵)
5		mnd4g.3	. . 3 ⊢ (𝜑 → 𝑌 ∈ 𝐵)
6		mnd4g.4	. . 3 ⊢ (𝜑 → 𝑍 ∈ 𝐵)
7		mndcl.b	. . . 4 ⊢ 𝐵 = (Base‘𝐺)
8		mndcl.p	. . . 4 ⊢ + = (+g‘𝐺)
9	7, 8	mndass 18703	. . 3 ⊢ ((𝐺 ∈ Mnd ∧ (𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((𝑋 + 𝑌) + 𝑍) = (𝑋 + (𝑌 + 𝑍)))
10	3, 4, 5, 6, 9	syl13anc 1370	. 2 ⊢ (𝜑 → ((𝑋 + 𝑌) + 𝑍) = (𝑋 + (𝑌 + 𝑍)))
11	7, 8	mndass 18703	. . 3 ⊢ ((𝐺 ∈ Mnd ∧ (𝑌 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((𝑌 + 𝑋) + 𝑍) = (𝑌 + (𝑋 + 𝑍)))
12	3, 5, 4, 6, 11	syl13anc 1370	. 2 ⊢ (𝜑 → ((𝑌 + 𝑋) + 𝑍) = (𝑌 + (𝑋 + 𝑍)))
13	2, 10, 12	3eqtr3d 2776	1 ⊢ (𝜑 → (𝑋 + (𝑌 + 𝑍)) = (𝑌 + (𝑋 + 𝑍)))

Syntax hints:   → wi 4   = wceq 1534   ∈ wcel 2099  ‘cfv 6548  (class class class)co 7420  Basecbs 17180  +_gcplusg 17233  Mndcmnd 18694

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1790  ax-4 1804  ax-5 1906  ax-6 1964  ax-7 2004  ax-8 2101  ax-9 2109  ax-ext 2699  ax-nul 5306

This theorem depends on definitions:  df-bi 206  df-an 396  df-or 847  df-3an 1087  df-tru 1537  df-fal 1547  df-ex 1775  df-sb 2061  df-clab 2706  df-cleq 2720  df-clel 2806  df-ne 2938  df-ral 3059  df-rex 3068  df-rab 3430  df-v 3473  df-sbc 3777  df-dif 3950  df-un 3952  df-in 3954  df-ss 3964  df-nul 4324  df-if 4530  df-sn 4630  df-pr 4632  df-op 4636  df-uni 4909  df-br 5149  df-iota 6500  df-fv 6556  df-ov 7423  df-sgrp 18679  df-mnd 18695

This theorem is referenced by:  mnd4g  18708  cmn12  19757