Proof of Theorem issgrpd
| Step | Hyp | Ref
 | Expression | 
| 1 |   | issgrpd.c | 
. . . . . . 7
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵) → (𝑥 + 𝑦) ∈ 𝐵) | 
| 2 | 1 | 3expib 1208 | 
. . . . . 6
⊢ (𝜑 → ((𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵) → (𝑥 + 𝑦) ∈ 𝐵)) | 
| 3 |   | issgrpd.b | 
. . . . . . . 8
⊢ (𝜑 → 𝐵 = (Base‘𝐺)) | 
| 4 | 3 | eleq2d 2266 | 
. . . . . . 7
⊢ (𝜑 → (𝑥 ∈ 𝐵 ↔ 𝑥 ∈ (Base‘𝐺))) | 
| 5 | 3 | eleq2d 2266 | 
. . . . . . 7
⊢ (𝜑 → (𝑦 ∈ 𝐵 ↔ 𝑦 ∈ (Base‘𝐺))) | 
| 6 | 4, 5 | anbi12d 473 | 
. . . . . 6
⊢ (𝜑 → ((𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵) ↔ (𝑥 ∈ (Base‘𝐺) ∧ 𝑦 ∈ (Base‘𝐺)))) | 
| 7 |   | issgrpd.p | 
. . . . . . . 8
⊢ (𝜑 → + =
(+g‘𝐺)) | 
| 8 | 7 | oveqd 5939 | 
. . . . . . 7
⊢ (𝜑 → (𝑥 + 𝑦) = (𝑥(+g‘𝐺)𝑦)) | 
| 9 | 8, 3 | eleq12d 2267 | 
. . . . . 6
⊢ (𝜑 → ((𝑥 + 𝑦) ∈ 𝐵 ↔ (𝑥(+g‘𝐺)𝑦) ∈ (Base‘𝐺))) | 
| 10 | 2, 6, 9 | 3imtr3d 202 | 
. . . . 5
⊢ (𝜑 → ((𝑥 ∈ (Base‘𝐺) ∧ 𝑦 ∈ (Base‘𝐺)) → (𝑥(+g‘𝐺)𝑦) ∈ (Base‘𝐺))) | 
| 11 | 10 | imp 124 | 
. . . 4
⊢ ((𝜑 ∧ (𝑥 ∈ (Base‘𝐺) ∧ 𝑦 ∈ (Base‘𝐺))) → (𝑥(+g‘𝐺)𝑦) ∈ (Base‘𝐺)) | 
| 12 |   | df-3an 982 | 
. . . . . . . . 9
⊢ ((𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ∧ 𝑧 ∈ 𝐵) ↔ ((𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵) ∧ 𝑧 ∈ 𝐵)) | 
| 13 |   | issgrpd.a | 
. . . . . . . . 9
⊢ ((𝜑 ∧ (𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ∧ 𝑧 ∈ 𝐵)) → ((𝑥 + 𝑦) + 𝑧) = (𝑥 + (𝑦 + 𝑧))) | 
| 14 | 12, 13 | sylan2br 288 | 
. . . . . . . 8
⊢ ((𝜑 ∧ ((𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵) ∧ 𝑧 ∈ 𝐵)) → ((𝑥 + 𝑦) + 𝑧) = (𝑥 + (𝑦 + 𝑧))) | 
| 15 | 14 | ex 115 | 
. . . . . . 7
⊢ (𝜑 → (((𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵) ∧ 𝑧 ∈ 𝐵) → ((𝑥 + 𝑦) + 𝑧) = (𝑥 + (𝑦 + 𝑧)))) | 
| 16 | 3 | eleq2d 2266 | 
. . . . . . . 8
⊢ (𝜑 → (𝑧 ∈ 𝐵 ↔ 𝑧 ∈ (Base‘𝐺))) | 
| 17 | 6, 16 | anbi12d 473 | 
. . . . . . 7
⊢ (𝜑 → (((𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵) ∧ 𝑧 ∈ 𝐵) ↔ ((𝑥 ∈ (Base‘𝐺) ∧ 𝑦 ∈ (Base‘𝐺)) ∧ 𝑧 ∈ (Base‘𝐺)))) | 
| 18 |   | eqidd 2197 | 
. . . . . . . . 9
⊢ (𝜑 → 𝑧 = 𝑧) | 
| 19 | 7, 8, 18 | oveq123d 5943 | 
. . . . . . . 8
⊢ (𝜑 → ((𝑥 + 𝑦) + 𝑧) = ((𝑥(+g‘𝐺)𝑦)(+g‘𝐺)𝑧)) | 
| 20 |   | eqidd 2197 | 
. . . . . . . . 9
⊢ (𝜑 → 𝑥 = 𝑥) | 
| 21 | 7 | oveqd 5939 | 
. . . . . . . . 9
⊢ (𝜑 → (𝑦 + 𝑧) = (𝑦(+g‘𝐺)𝑧)) | 
| 22 | 7, 20, 21 | oveq123d 5943 | 
. . . . . . . 8
⊢ (𝜑 → (𝑥 + (𝑦 + 𝑧)) = (𝑥(+g‘𝐺)(𝑦(+g‘𝐺)𝑧))) | 
| 23 | 19, 22 | eqeq12d 2211 | 
. . . . . . 7
⊢ (𝜑 → (((𝑥 + 𝑦) + 𝑧) = (𝑥 + (𝑦 + 𝑧)) ↔ ((𝑥(+g‘𝐺)𝑦)(+g‘𝐺)𝑧) = (𝑥(+g‘𝐺)(𝑦(+g‘𝐺)𝑧)))) | 
| 24 | 15, 17, 23 | 3imtr3d 202 | 
. . . . . 6
⊢ (𝜑 → (((𝑥 ∈ (Base‘𝐺) ∧ 𝑦 ∈ (Base‘𝐺)) ∧ 𝑧 ∈ (Base‘𝐺)) → ((𝑥(+g‘𝐺)𝑦)(+g‘𝐺)𝑧) = (𝑥(+g‘𝐺)(𝑦(+g‘𝐺)𝑧)))) | 
| 25 | 24 | impl 380 | 
. . . . 5
⊢ (((𝜑 ∧ (𝑥 ∈ (Base‘𝐺) ∧ 𝑦 ∈ (Base‘𝐺))) ∧ 𝑧 ∈ (Base‘𝐺)) → ((𝑥(+g‘𝐺)𝑦)(+g‘𝐺)𝑧) = (𝑥(+g‘𝐺)(𝑦(+g‘𝐺)𝑧))) | 
| 26 | 25 | ralrimiva 2570 | 
. . . 4
⊢ ((𝜑 ∧ (𝑥 ∈ (Base‘𝐺) ∧ 𝑦 ∈ (Base‘𝐺))) → ∀𝑧 ∈ (Base‘𝐺)((𝑥(+g‘𝐺)𝑦)(+g‘𝐺)𝑧) = (𝑥(+g‘𝐺)(𝑦(+g‘𝐺)𝑧))) | 
| 27 | 11, 26 | jca 306 | 
. . 3
⊢ ((𝜑 ∧ (𝑥 ∈ (Base‘𝐺) ∧ 𝑦 ∈ (Base‘𝐺))) → ((𝑥(+g‘𝐺)𝑦) ∈ (Base‘𝐺) ∧ ∀𝑧 ∈ (Base‘𝐺)((𝑥(+g‘𝐺)𝑦)(+g‘𝐺)𝑧) = (𝑥(+g‘𝐺)(𝑦(+g‘𝐺)𝑧)))) | 
| 28 | 27 | ralrimivva 2579 | 
. 2
⊢ (𝜑 → ∀𝑥 ∈ (Base‘𝐺)∀𝑦 ∈ (Base‘𝐺)((𝑥(+g‘𝐺)𝑦) ∈ (Base‘𝐺) ∧ ∀𝑧 ∈ (Base‘𝐺)((𝑥(+g‘𝐺)𝑦)(+g‘𝐺)𝑧) = (𝑥(+g‘𝐺)(𝑦(+g‘𝐺)𝑧)))) | 
| 29 |   | issgrpd.v | 
. . 3
⊢ (𝜑 → 𝐺 ∈ 𝑉) | 
| 30 |   | eqid 2196 | 
. . . 4
⊢
(Base‘𝐺) =
(Base‘𝐺) | 
| 31 |   | eqid 2196 | 
. . . 4
⊢
(+g‘𝐺) = (+g‘𝐺) | 
| 32 | 30, 31 | issgrpv 13047 | 
. . 3
⊢ (𝐺 ∈ 𝑉 → (𝐺 ∈ Smgrp ↔ ∀𝑥 ∈ (Base‘𝐺)∀𝑦 ∈ (Base‘𝐺)((𝑥(+g‘𝐺)𝑦) ∈ (Base‘𝐺) ∧ ∀𝑧 ∈ (Base‘𝐺)((𝑥(+g‘𝐺)𝑦)(+g‘𝐺)𝑧) = (𝑥(+g‘𝐺)(𝑦(+g‘𝐺)𝑧))))) | 
| 33 | 29, 32 | syl 14 | 
. 2
⊢ (𝜑 → (𝐺 ∈ Smgrp ↔ ∀𝑥 ∈ (Base‘𝐺)∀𝑦 ∈ (Base‘𝐺)((𝑥(+g‘𝐺)𝑦) ∈ (Base‘𝐺) ∧ ∀𝑧 ∈ (Base‘𝐺)((𝑥(+g‘𝐺)𝑦)(+g‘𝐺)𝑧) = (𝑥(+g‘𝐺)(𝑦(+g‘𝐺)𝑧))))) | 
| 34 | 28, 33 | mpbird 167 | 
1
⊢ (𝜑 → 𝐺 ∈ Smgrp) |