Proof of Theorem grplcan
| Step | Hyp | Ref
 | Expression | 
| 1 |   | oveq2 5930 | 
. . . . . 6
⊢ ((𝑍 + 𝑋) = (𝑍 + 𝑌) → (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑋)) = (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑌))) | 
| 2 | 1 | adantl 277 | 
. . . . 5
⊢ ((((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) ∧ (𝑍 + 𝑋) = (𝑍 + 𝑌)) → (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑋)) = (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑌))) | 
| 3 |   | grplcan.b | 
. . . . . . . . . . 11
⊢ 𝐵 = (Base‘𝐺) | 
| 4 |   | grplcan.p | 
. . . . . . . . . . 11
⊢  + =
(+g‘𝐺) | 
| 5 |   | eqid 2196 | 
. . . . . . . . . . 11
⊢
(0g‘𝐺) = (0g‘𝐺) | 
| 6 |   | eqid 2196 | 
. . . . . . . . . . 11
⊢
(invg‘𝐺) = (invg‘𝐺) | 
| 7 | 3, 4, 5, 6 | grplinv 13182 | 
. . . . . . . . . 10
⊢ ((𝐺 ∈ Grp ∧ 𝑍 ∈ 𝐵) → (((invg‘𝐺)‘𝑍) + 𝑍) = (0g‘𝐺)) | 
| 8 | 7 | adantlr 477 | 
. . . . . . . . 9
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑍 ∈ 𝐵) → (((invg‘𝐺)‘𝑍) + 𝑍) = (0g‘𝐺)) | 
| 9 | 8 | oveq1d 5937 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑍 ∈ 𝐵) → ((((invg‘𝐺)‘𝑍) + 𝑍) + 𝑋) = ((0g‘𝐺) + 𝑋)) | 
| 10 | 3, 6 | grpinvcl 13180 | 
. . . . . . . . . . . 12
⊢ ((𝐺 ∈ Grp ∧ 𝑍 ∈ 𝐵) → ((invg‘𝐺)‘𝑍) ∈ 𝐵) | 
| 11 | 10 | adantrl 478 | 
. . . . . . . . . . 11
⊢ ((𝐺 ∈ Grp ∧ (𝑋 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((invg‘𝐺)‘𝑍) ∈ 𝐵) | 
| 12 |   | simprr 531 | 
. . . . . . . . . . 11
⊢ ((𝐺 ∈ Grp ∧ (𝑋 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → 𝑍 ∈ 𝐵) | 
| 13 |   | simprl 529 | 
. . . . . . . . . . 11
⊢ ((𝐺 ∈ Grp ∧ (𝑋 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → 𝑋 ∈ 𝐵) | 
| 14 | 11, 12, 13 | 3jca 1179 | 
. . . . . . . . . 10
⊢ ((𝐺 ∈ Grp ∧ (𝑋 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → (((invg‘𝐺)‘𝑍) ∈ 𝐵 ∧ 𝑍 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵)) | 
| 15 | 3, 4 | grpass 13141 | 
. . . . . . . . . 10
⊢ ((𝐺 ∈ Grp ∧
(((invg‘𝐺)‘𝑍) ∈ 𝐵 ∧ 𝑍 ∈ 𝐵 ∧ 𝑋 ∈ 𝐵)) → ((((invg‘𝐺)‘𝑍) + 𝑍) + 𝑋) = (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑋))) | 
| 16 | 14, 15 | syldan 282 | 
. . . . . . . . 9
⊢ ((𝐺 ∈ Grp ∧ (𝑋 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((((invg‘𝐺)‘𝑍) + 𝑍) + 𝑋) = (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑋))) | 
| 17 | 16 | anassrs 400 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑍 ∈ 𝐵) → ((((invg‘𝐺)‘𝑍) + 𝑍) + 𝑋) = (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑋))) | 
| 18 | 3, 4, 5 | grplid 13163 | 
. . . . . . . . 9
⊢ ((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) → ((0g‘𝐺) + 𝑋) = 𝑋) | 
| 19 | 18 | adantr 276 | 
. . . . . . . 8
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑍 ∈ 𝐵) → ((0g‘𝐺) + 𝑋) = 𝑋) | 
| 20 | 9, 17, 19 | 3eqtr3d 2237 | 
. . . . . . 7
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ 𝑍 ∈ 𝐵) → (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑋)) = 𝑋) | 
| 21 | 20 | adantrl 478 | 
. . . . . 6
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑋)) = 𝑋) | 
| 22 | 21 | adantr 276 | 
. . . . 5
⊢ ((((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) ∧ (𝑍 + 𝑋) = (𝑍 + 𝑌)) → (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑋)) = 𝑋) | 
| 23 | 7 | adantrl 478 | 
. . . . . . . . 9
⊢ ((𝐺 ∈ Grp ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → (((invg‘𝐺)‘𝑍) + 𝑍) = (0g‘𝐺)) | 
| 24 | 23 | oveq1d 5937 | 
. . . . . . . 8
⊢ ((𝐺 ∈ Grp ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((((invg‘𝐺)‘𝑍) + 𝑍) + 𝑌) = ((0g‘𝐺) + 𝑌)) | 
| 25 | 10 | adantrl 478 | 
. . . . . . . . . 10
⊢ ((𝐺 ∈ Grp ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((invg‘𝐺)‘𝑍) ∈ 𝐵) | 
| 26 |   | simprr 531 | 
. . . . . . . . . 10
⊢ ((𝐺 ∈ Grp ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → 𝑍 ∈ 𝐵) | 
| 27 |   | simprl 529 | 
. . . . . . . . . 10
⊢ ((𝐺 ∈ Grp ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → 𝑌 ∈ 𝐵) | 
| 28 | 25, 26, 27 | 3jca 1179 | 
. . . . . . . . 9
⊢ ((𝐺 ∈ Grp ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → (((invg‘𝐺)‘𝑍) ∈ 𝐵 ∧ 𝑍 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵)) | 
| 29 | 3, 4 | grpass 13141 | 
. . . . . . . . 9
⊢ ((𝐺 ∈ Grp ∧
(((invg‘𝐺)‘𝑍) ∈ 𝐵 ∧ 𝑍 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵)) → ((((invg‘𝐺)‘𝑍) + 𝑍) + 𝑌) = (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑌))) | 
| 30 | 28, 29 | syldan 282 | 
. . . . . . . 8
⊢ ((𝐺 ∈ Grp ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((((invg‘𝐺)‘𝑍) + 𝑍) + 𝑌) = (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑌))) | 
| 31 | 3, 4, 5 | grplid 13163 | 
. . . . . . . . 9
⊢ ((𝐺 ∈ Grp ∧ 𝑌 ∈ 𝐵) → ((0g‘𝐺) + 𝑌) = 𝑌) | 
| 32 | 31 | adantrr 479 | 
. . . . . . . 8
⊢ ((𝐺 ∈ Grp ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((0g‘𝐺) + 𝑌) = 𝑌) | 
| 33 | 24, 30, 32 | 3eqtr3d 2237 | 
. . . . . . 7
⊢ ((𝐺 ∈ Grp ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑌)) = 𝑌) | 
| 34 | 33 | adantlr 477 | 
. . . . . 6
⊢ (((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑌)) = 𝑌) | 
| 35 | 34 | adantr 276 | 
. . . . 5
⊢ ((((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) ∧ (𝑍 + 𝑋) = (𝑍 + 𝑌)) → (((invg‘𝐺)‘𝑍) + (𝑍 + 𝑌)) = 𝑌) | 
| 36 | 2, 22, 35 | 3eqtr3d 2237 | 
. . . 4
⊢ ((((𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵) ∧ (𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) ∧ (𝑍 + 𝑋) = (𝑍 + 𝑌)) → 𝑋 = 𝑌) | 
| 37 | 36 | exp53 377 | 
. . 3
⊢ (𝐺 ∈ Grp → (𝑋 ∈ 𝐵 → (𝑌 ∈ 𝐵 → (𝑍 ∈ 𝐵 → ((𝑍 + 𝑋) = (𝑍 + 𝑌) → 𝑋 = 𝑌))))) | 
| 38 | 37 | 3imp2 1224 | 
. 2
⊢ ((𝐺 ∈ Grp ∧ (𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((𝑍 + 𝑋) = (𝑍 + 𝑌) → 𝑋 = 𝑌)) | 
| 39 |   | oveq2 5930 | 
. 2
⊢ (𝑋 = 𝑌 → (𝑍 + 𝑋) = (𝑍 + 𝑌)) | 
| 40 | 38, 39 | impbid1 142 | 
1
⊢ ((𝐺 ∈ Grp ∧ (𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((𝑍 + 𝑋) = (𝑍 + 𝑌) ↔ 𝑋 = 𝑌)) |