| Step | Hyp | Ref
| Expression |
| 1 | | grpsubval.m |
. . 3
⊢ − =
(-g‘𝐺) |
| 2 | | fveq2 6906 |
. . . . . 6
⊢ (𝑔 = 𝐺 → (Base‘𝑔) = (Base‘𝐺)) |
| 3 | | grpsubval.b |
. . . . . 6
⊢ 𝐵 = (Base‘𝐺) |
| 4 | 2, 3 | eqtr4di 2795 |
. . . . 5
⊢ (𝑔 = 𝐺 → (Base‘𝑔) = 𝐵) |
| 5 | | fveq2 6906 |
. . . . . . 7
⊢ (𝑔 = 𝐺 → (+g‘𝑔) = (+g‘𝐺)) |
| 6 | | grpsubval.p |
. . . . . . 7
⊢ + =
(+g‘𝐺) |
| 7 | 5, 6 | eqtr4di 2795 |
. . . . . 6
⊢ (𝑔 = 𝐺 → (+g‘𝑔) = + ) |
| 8 | | eqidd 2738 |
. . . . . 6
⊢ (𝑔 = 𝐺 → 𝑥 = 𝑥) |
| 9 | | fveq2 6906 |
. . . . . . . 8
⊢ (𝑔 = 𝐺 → (invg‘𝑔) = (invg‘𝐺)) |
| 10 | | grpsubval.i |
. . . . . . . 8
⊢ 𝐼 = (invg‘𝐺) |
| 11 | 9, 10 | eqtr4di 2795 |
. . . . . . 7
⊢ (𝑔 = 𝐺 → (invg‘𝑔) = 𝐼) |
| 12 | 11 | fveq1d 6908 |
. . . . . 6
⊢ (𝑔 = 𝐺 → ((invg‘𝑔)‘𝑦) = (𝐼‘𝑦)) |
| 13 | 7, 8, 12 | oveq123d 7452 |
. . . . 5
⊢ (𝑔 = 𝐺 → (𝑥(+g‘𝑔)((invg‘𝑔)‘𝑦)) = (𝑥 + (𝐼‘𝑦))) |
| 14 | 4, 4, 13 | mpoeq123dv 7508 |
. . . 4
⊢ (𝑔 = 𝐺 → (𝑥 ∈ (Base‘𝑔), 𝑦 ∈ (Base‘𝑔) ↦ (𝑥(+g‘𝑔)((invg‘𝑔)‘𝑦))) = (𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (𝑥 + (𝐼‘𝑦)))) |
| 15 | | df-sbg 18956 |
. . . 4
⊢
-g = (𝑔
∈ V ↦ (𝑥 ∈
(Base‘𝑔), 𝑦 ∈ (Base‘𝑔) ↦ (𝑥(+g‘𝑔)((invg‘𝑔)‘𝑦)))) |
| 16 | 3 | fvexi 6920 |
. . . . 5
⊢ 𝐵 ∈ V |
| 17 | 6 | fvexi 6920 |
. . . . . . 7
⊢ + ∈
V |
| 18 | 17 | rnex 7932 |
. . . . . 6
⊢ ran + ∈
V |
| 19 | | p0ex 5384 |
. . . . . 6
⊢ {∅}
∈ V |
| 20 | 18, 19 | unex 7764 |
. . . . 5
⊢ (ran
+ ∪
{∅}) ∈ V |
| 21 | | df-ov 7434 |
. . . . . . 7
⊢ (𝑥 + (𝐼‘𝑦)) = ( + ‘〈𝑥, (𝐼‘𝑦)〉) |
| 22 | | fvrn0 6936 |
. . . . . . 7
⊢ ( +
‘〈𝑥, (𝐼‘𝑦)〉) ∈ (ran + ∪
{∅}) |
| 23 | 21, 22 | eqeltri 2837 |
. . . . . 6
⊢ (𝑥 + (𝐼‘𝑦)) ∈ (ran + ∪
{∅}) |
| 24 | 23 | rgen2w 3066 |
. . . . 5
⊢
∀𝑥 ∈
𝐵 ∀𝑦 ∈ 𝐵 (𝑥 + (𝐼‘𝑦)) ∈ (ran + ∪
{∅}) |
| 25 | 16, 16, 20, 24 | mpoexw 8103 |
. . . 4
⊢ (𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (𝑥 + (𝐼‘𝑦))) ∈ V |
| 26 | 14, 15, 25 | fvmpt 7016 |
. . 3
⊢ (𝐺 ∈ V →
(-g‘𝐺) =
(𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (𝑥 + (𝐼‘𝑦)))) |
| 27 | 1, 26 | eqtrid 2789 |
. 2
⊢ (𝐺 ∈ V → − =
(𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (𝑥 + (𝐼‘𝑦)))) |
| 28 | | fvprc 6898 |
. . . 4
⊢ (¬
𝐺 ∈ V →
(-g‘𝐺) =
∅) |
| 29 | 1, 28 | eqtrid 2789 |
. . 3
⊢ (¬
𝐺 ∈ V → − =
∅) |
| 30 | | fvprc 6898 |
. . . . . 6
⊢ (¬
𝐺 ∈ V →
(Base‘𝐺) =
∅) |
| 31 | 3, 30 | eqtrid 2789 |
. . . . 5
⊢ (¬
𝐺 ∈ V → 𝐵 = ∅) |
| 32 | 31 | olcd 875 |
. . . 4
⊢ (¬
𝐺 ∈ V → (𝐵 = ∅ ∨ 𝐵 = ∅)) |
| 33 | | 0mpo0 7516 |
. . . 4
⊢ ((𝐵 = ∅ ∨ 𝐵 = ∅) → (𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (𝑥 + (𝐼‘𝑦))) = ∅) |
| 34 | 32, 33 | syl 17 |
. . 3
⊢ (¬
𝐺 ∈ V → (𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (𝑥 + (𝐼‘𝑦))) = ∅) |
| 35 | 29, 34 | eqtr4d 2780 |
. 2
⊢ (¬
𝐺 ∈ V → − =
(𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (𝑥 + (𝐼‘𝑦)))) |
| 36 | 27, 35 | pm2.61i 182 |
1
⊢ − =
(𝑥 ∈ 𝐵, 𝑦 ∈ 𝐵 ↦ (𝑥 + (𝐼‘𝑦))) |