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Theorem grpridd 7151
 Description: Deduce right identity from left inverse and left identity in an associative structure (such as a group). (Contributed by NM, 10-Aug-2013.) (Proof shortened by Mario Carneiro, 6-Jan-2015.)
Hypotheses
Ref Expression
grprinvlem.c ((𝜑𝑥𝐵𝑦𝐵) → (𝑥 + 𝑦) ∈ 𝐵)
grprinvlem.o (𝜑𝑂𝐵)
grprinvlem.i ((𝜑𝑥𝐵) → (𝑂 + 𝑥) = 𝑥)
grprinvlem.a ((𝜑 ∧ (𝑥𝐵𝑦𝐵𝑧𝐵)) → ((𝑥 + 𝑦) + 𝑧) = (𝑥 + (𝑦 + 𝑧)))
grprinvlem.n ((𝜑𝑥𝐵) → ∃𝑦𝐵 (𝑦 + 𝑥) = 𝑂)
Assertion
Ref Expression
grpridd ((𝜑𝑥𝐵) → (𝑥 + 𝑂) = 𝑥)
Distinct variable groups:   𝑥,𝑦,𝑧,𝐵   𝑥,𝑂,𝑦,𝑧   𝜑,𝑥,𝑦,𝑧   𝑥, + ,𝑦,𝑧

Proof of Theorem grpridd
Dummy variables 𝑢 𝑛 𝑣 𝑤 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 grprinvlem.n . . . 4 ((𝜑𝑥𝐵) → ∃𝑦𝐵 (𝑦 + 𝑥) = 𝑂)
2 oveq1 6929 . . . . . 6 (𝑦 = 𝑛 → (𝑦 + 𝑥) = (𝑛 + 𝑥))
32eqeq1d 2780 . . . . 5 (𝑦 = 𝑛 → ((𝑦 + 𝑥) = 𝑂 ↔ (𝑛 + 𝑥) = 𝑂))
43cbvrexv 3368 . . . 4 (∃𝑦𝐵 (𝑦 + 𝑥) = 𝑂 ↔ ∃𝑛𝐵 (𝑛 + 𝑥) = 𝑂)
51, 4sylib 210 . . 3 ((𝜑𝑥𝐵) → ∃𝑛𝐵 (𝑛 + 𝑥) = 𝑂)
6 grprinvlem.a . . . . . . . 8 ((𝜑 ∧ (𝑥𝐵𝑦𝐵𝑧𝐵)) → ((𝑥 + 𝑦) + 𝑧) = (𝑥 + (𝑦 + 𝑧)))
76caovassg 7109 . . . . . . 7 ((𝜑 ∧ (𝑢𝐵𝑣𝐵𝑤𝐵)) → ((𝑢 + 𝑣) + 𝑤) = (𝑢 + (𝑣 + 𝑤)))
87adantlr 705 . . . . . 6 (((𝜑 ∧ (𝑥𝐵 ∧ (𝑛𝐵 ∧ (𝑛 + 𝑥) = 𝑂))) ∧ (𝑢𝐵𝑣𝐵𝑤𝐵)) → ((𝑢 + 𝑣) + 𝑤) = (𝑢 + (𝑣 + 𝑤)))
9 simprl 761 . . . . . 6 ((𝜑 ∧ (𝑥𝐵 ∧ (𝑛𝐵 ∧ (𝑛 + 𝑥) = 𝑂))) → 𝑥𝐵)
10 simprrl 771 . . . . . 6 ((𝜑 ∧ (𝑥𝐵 ∧ (𝑛𝐵 ∧ (𝑛 + 𝑥) = 𝑂))) → 𝑛𝐵)
118, 9, 10, 9caovassd 7110 . . . . 5 ((𝜑 ∧ (𝑥𝐵 ∧ (𝑛𝐵 ∧ (𝑛 + 𝑥) = 𝑂))) → ((𝑥 + 𝑛) + 𝑥) = (𝑥 + (𝑛 + 𝑥)))
12 grprinvlem.c . . . . . . 7 ((𝜑𝑥𝐵𝑦𝐵) → (𝑥 + 𝑦) ∈ 𝐵)
13 grprinvlem.o . . . . . . 7 (𝜑𝑂𝐵)
14 grprinvlem.i . . . . . . 7 ((𝜑𝑥𝐵) → (𝑂 + 𝑥) = 𝑥)
15 simprrr 772 . . . . . . 7 ((𝜑 ∧ (𝑥𝐵 ∧ (𝑛𝐵 ∧ (𝑛 + 𝑥) = 𝑂))) → (𝑛 + 𝑥) = 𝑂)
1612, 13, 14, 6, 1, 9, 10, 15grprinvd 7150 . . . . . 6 ((𝜑 ∧ (𝑥𝐵 ∧ (𝑛𝐵 ∧ (𝑛 + 𝑥) = 𝑂))) → (𝑥 + 𝑛) = 𝑂)
1716oveq1d 6937 . . . . 5 ((𝜑 ∧ (𝑥𝐵 ∧ (𝑛𝐵 ∧ (𝑛 + 𝑥) = 𝑂))) → ((𝑥 + 𝑛) + 𝑥) = (𝑂 + 𝑥))
1815oveq2d 6938 . . . . 5 ((𝜑 ∧ (𝑥𝐵 ∧ (𝑛𝐵 ∧ (𝑛 + 𝑥) = 𝑂))) → (𝑥 + (𝑛 + 𝑥)) = (𝑥 + 𝑂))
1911, 17, 183eqtr3d 2822 . . . 4 ((𝜑 ∧ (𝑥𝐵 ∧ (𝑛𝐵 ∧ (𝑛 + 𝑥) = 𝑂))) → (𝑂 + 𝑥) = (𝑥 + 𝑂))
2019anassrs 461 . . 3 (((𝜑𝑥𝐵) ∧ (𝑛𝐵 ∧ (𝑛 + 𝑥) = 𝑂)) → (𝑂 + 𝑥) = (𝑥 + 𝑂))
215, 20rexlimddv 3218 . 2 ((𝜑𝑥𝐵) → (𝑂 + 𝑥) = (𝑥 + 𝑂))
2221, 14eqtr3d 2816 1 ((𝜑𝑥𝐵) → (𝑥 + 𝑂) = 𝑥)
 Colors of variables: wff setvar class Syntax hints:   → wi 4   ∧ wa 386   ∧ w3a 1071   = wceq 1601   ∈ wcel 2107  ∃wrex 3091  (class class class)co 6922 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1839  ax-4 1853  ax-5 1953  ax-6 2021  ax-7 2055  ax-9 2116  ax-10 2135  ax-11 2150  ax-12 2163  ax-13 2334  ax-ext 2754 This theorem depends on definitions:  df-bi 199  df-an 387  df-or 837  df-3an 1073  df-tru 1605  df-ex 1824  df-nf 1828  df-sb 2012  df-clab 2764  df-cleq 2770  df-clel 2774  df-nfc 2921  df-ral 3095  df-rex 3096  df-rab 3099  df-v 3400  df-dif 3795  df-un 3797  df-in 3799  df-ss 3806  df-nul 4142  df-if 4308  df-sn 4399  df-pr 4401  df-op 4405  df-uni 4672  df-br 4887  df-iota 6099  df-fv 6143  df-ov 6925 This theorem is referenced by:  isgrpde  17830
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