Step | Hyp | Ref
| Expression |
1 | | grpkerinj.2 |
. . . . . . . . 9
⊢ 𝑊 = (GId‘𝐺) |
2 | | grpkerinj.4 |
. . . . . . . . 9
⊢ 𝑈 = (GId‘𝐻) |
3 | 1, 2 | ghomidOLD 35784 |
. . . . . . . 8
⊢ ((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) → (𝐹‘𝑊) = 𝑈) |
4 | 3 | sneqd 4553 |
. . . . . . 7
⊢ ((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) → {(𝐹‘𝑊)} = {𝑈}) |
5 | | grpkerinj.1 |
. . . . . . . . . 10
⊢ 𝑋 = ran 𝐺 |
6 | | grpkerinj.3 |
. . . . . . . . . 10
⊢ 𝑌 = ran 𝐻 |
7 | 5, 6 | ghomf 35785 |
. . . . . . . . 9
⊢ ((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) → 𝐹:𝑋⟶𝑌) |
8 | 7 | ffnd 6546 |
. . . . . . . 8
⊢ ((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) → 𝐹 Fn 𝑋) |
9 | 5, 1 | grpoidcl 28595 |
. . . . . . . . 9
⊢ (𝐺 ∈ GrpOp → 𝑊 ∈ 𝑋) |
10 | 9 | 3ad2ant1 1135 |
. . . . . . . 8
⊢ ((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) → 𝑊 ∈ 𝑋) |
11 | | fnsnfv 6790 |
. . . . . . . 8
⊢ ((𝐹 Fn 𝑋 ∧ 𝑊 ∈ 𝑋) → {(𝐹‘𝑊)} = (𝐹 “ {𝑊})) |
12 | 8, 10, 11 | syl2anc 587 |
. . . . . . 7
⊢ ((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) → {(𝐹‘𝑊)} = (𝐹 “ {𝑊})) |
13 | 4, 12 | eqtr3d 2779 |
. . . . . 6
⊢ ((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) → {𝑈} = (𝐹 “ {𝑊})) |
14 | 13 | imaeq2d 5929 |
. . . . 5
⊢ ((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) → (◡𝐹 “ {𝑈}) = (◡𝐹 “ (𝐹 “ {𝑊}))) |
15 | 14 | adantl 485 |
. . . 4
⊢ ((𝐹:𝑋–1-1→𝑌 ∧ (𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻))) → (◡𝐹 “ {𝑈}) = (◡𝐹 “ (𝐹 “ {𝑊}))) |
16 | 9 | snssd 4722 |
. . . . . 6
⊢ (𝐺 ∈ GrpOp → {𝑊} ⊆ 𝑋) |
17 | 16 | 3ad2ant1 1135 |
. . . . 5
⊢ ((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) → {𝑊} ⊆ 𝑋) |
18 | | f1imacnv 6677 |
. . . . 5
⊢ ((𝐹:𝑋–1-1→𝑌 ∧ {𝑊} ⊆ 𝑋) → (◡𝐹 “ (𝐹 “ {𝑊})) = {𝑊}) |
19 | 17, 18 | sylan2 596 |
. . . 4
⊢ ((𝐹:𝑋–1-1→𝑌 ∧ (𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻))) → (◡𝐹 “ (𝐹 “ {𝑊})) = {𝑊}) |
20 | 15, 19 | eqtrd 2777 |
. . 3
⊢ ((𝐹:𝑋–1-1→𝑌 ∧ (𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻))) → (◡𝐹 “ {𝑈}) = {𝑊}) |
21 | 20 | expcom 417 |
. 2
⊢ ((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) → (𝐹:𝑋–1-1→𝑌 → (◡𝐹 “ {𝑈}) = {𝑊})) |
22 | 7 | adantr 484 |
. . . 4
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (◡𝐹 “ {𝑈}) = {𝑊}) → 𝐹:𝑋⟶𝑌) |
23 | | simpl2 1194 |
. . . . . . . 8
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → 𝐻 ∈ GrpOp) |
24 | 7 | ffvelrnda 6904 |
. . . . . . . . 9
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ 𝑥 ∈ 𝑋) → (𝐹‘𝑥) ∈ 𝑌) |
25 | 24 | adantrr 717 |
. . . . . . . 8
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → (𝐹‘𝑥) ∈ 𝑌) |
26 | 7 | ffvelrnda 6904 |
. . . . . . . . 9
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ 𝑦 ∈ 𝑋) → (𝐹‘𝑦) ∈ 𝑌) |
27 | 26 | adantrl 716 |
. . . . . . . 8
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → (𝐹‘𝑦) ∈ 𝑌) |
28 | | eqid 2737 |
. . . . . . . . 9
⊢ (
/𝑔 ‘𝐻) = ( /𝑔 ‘𝐻) |
29 | 6, 2, 28 | grpoeqdivid 35776 |
. . . . . . . 8
⊢ ((𝐻 ∈ GrpOp ∧ (𝐹‘𝑥) ∈ 𝑌 ∧ (𝐹‘𝑦) ∈ 𝑌) → ((𝐹‘𝑥) = (𝐹‘𝑦) ↔ ((𝐹‘𝑥)( /𝑔 ‘𝐻)(𝐹‘𝑦)) = 𝑈)) |
30 | 23, 25, 27, 29 | syl3anc 1373 |
. . . . . . 7
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → ((𝐹‘𝑥) = (𝐹‘𝑦) ↔ ((𝐹‘𝑥)( /𝑔 ‘𝐻)(𝐹‘𝑦)) = 𝑈)) |
31 | 30 | adantlr 715 |
. . . . . 6
⊢ ((((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (◡𝐹 “ {𝑈}) = {𝑊}) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → ((𝐹‘𝑥) = (𝐹‘𝑦) ↔ ((𝐹‘𝑥)( /𝑔 ‘𝐻)(𝐹‘𝑦)) = 𝑈)) |
32 | | eqid 2737 |
. . . . . . . . . 10
⊢ (
/𝑔 ‘𝐺) = ( /𝑔 ‘𝐺) |
33 | 5, 32, 28 | ghomdiv 35787 |
. . . . . . . . 9
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → (𝐹‘(𝑥( /𝑔 ‘𝐺)𝑦)) = ((𝐹‘𝑥)( /𝑔 ‘𝐻)(𝐹‘𝑦))) |
34 | 33 | adantlr 715 |
. . . . . . . 8
⊢ ((((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (◡𝐹 “ {𝑈}) = {𝑊}) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → (𝐹‘(𝑥( /𝑔 ‘𝐺)𝑦)) = ((𝐹‘𝑥)( /𝑔 ‘𝐻)(𝐹‘𝑦))) |
35 | 34 | eqeq1d 2739 |
. . . . . . 7
⊢ ((((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (◡𝐹 “ {𝑈}) = {𝑊}) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → ((𝐹‘(𝑥( /𝑔 ‘𝐺)𝑦)) = 𝑈 ↔ ((𝐹‘𝑥)( /𝑔 ‘𝐻)(𝐹‘𝑦)) = 𝑈)) |
36 | 2 | fvexi 6731 |
. . . . . . . . . 10
⊢ 𝑈 ∈ V |
37 | 36 | snid 4577 |
. . . . . . . . 9
⊢ 𝑈 ∈ {𝑈} |
38 | | eleq1 2825 |
. . . . . . . . 9
⊢ ((𝐹‘(𝑥( /𝑔 ‘𝐺)𝑦)) = 𝑈 → ((𝐹‘(𝑥( /𝑔 ‘𝐺)𝑦)) ∈ {𝑈} ↔ 𝑈 ∈ {𝑈})) |
39 | 37, 38 | mpbiri 261 |
. . . . . . . 8
⊢ ((𝐹‘(𝑥( /𝑔 ‘𝐺)𝑦)) = 𝑈 → (𝐹‘(𝑥( /𝑔 ‘𝐺)𝑦)) ∈ {𝑈}) |
40 | 7 | ffund 6549 |
. . . . . . . . . . . . 13
⊢ ((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) → Fun 𝐹) |
41 | 40 | adantr 484 |
. . . . . . . . . . . 12
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → Fun 𝐹) |
42 | 5, 32 | grpodivcl 28620 |
. . . . . . . . . . . . . . 15
⊢ ((𝐺 ∈ GrpOp ∧ 𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋) → (𝑥( /𝑔 ‘𝐺)𝑦) ∈ 𝑋) |
43 | 42 | 3expb 1122 |
. . . . . . . . . . . . . 14
⊢ ((𝐺 ∈ GrpOp ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → (𝑥( /𝑔 ‘𝐺)𝑦) ∈ 𝑋) |
44 | 43 | 3ad2antl1 1187 |
. . . . . . . . . . . . 13
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → (𝑥( /𝑔 ‘𝐺)𝑦) ∈ 𝑋) |
45 | 7 | fdmd 6556 |
. . . . . . . . . . . . . 14
⊢ ((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) → dom 𝐹 = 𝑋) |
46 | 45 | adantr 484 |
. . . . . . . . . . . . 13
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → dom 𝐹 = 𝑋) |
47 | 44, 46 | eleqtrrd 2841 |
. . . . . . . . . . . 12
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → (𝑥( /𝑔 ‘𝐺)𝑦) ∈ dom 𝐹) |
48 | | fvimacnv 6873 |
. . . . . . . . . . . 12
⊢ ((Fun
𝐹 ∧ (𝑥( /𝑔 ‘𝐺)𝑦) ∈ dom 𝐹) → ((𝐹‘(𝑥( /𝑔 ‘𝐺)𝑦)) ∈ {𝑈} ↔ (𝑥( /𝑔 ‘𝐺)𝑦) ∈ (◡𝐹 “ {𝑈}))) |
49 | 41, 47, 48 | syl2anc 587 |
. . . . . . . . . . 11
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → ((𝐹‘(𝑥( /𝑔 ‘𝐺)𝑦)) ∈ {𝑈} ↔ (𝑥( /𝑔 ‘𝐺)𝑦) ∈ (◡𝐹 “ {𝑈}))) |
50 | | eleq2 2826 |
. . . . . . . . . . 11
⊢ ((◡𝐹 “ {𝑈}) = {𝑊} → ((𝑥( /𝑔 ‘𝐺)𝑦) ∈ (◡𝐹 “ {𝑈}) ↔ (𝑥( /𝑔 ‘𝐺)𝑦) ∈ {𝑊})) |
51 | 49, 50 | sylan9bb 513 |
. . . . . . . . . 10
⊢ ((((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) ∧ (◡𝐹 “ {𝑈}) = {𝑊}) → ((𝐹‘(𝑥( /𝑔 ‘𝐺)𝑦)) ∈ {𝑈} ↔ (𝑥( /𝑔 ‘𝐺)𝑦) ∈ {𝑊})) |
52 | 51 | an32s 652 |
. . . . . . . . 9
⊢ ((((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (◡𝐹 “ {𝑈}) = {𝑊}) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → ((𝐹‘(𝑥( /𝑔 ‘𝐺)𝑦)) ∈ {𝑈} ↔ (𝑥( /𝑔 ‘𝐺)𝑦) ∈ {𝑊})) |
53 | | elsni 4558 |
. . . . . . . . . . 11
⊢ ((𝑥( /𝑔
‘𝐺)𝑦) ∈ {𝑊} → (𝑥( /𝑔 ‘𝐺)𝑦) = 𝑊) |
54 | 5, 1, 32 | grpoeqdivid 35776 |
. . . . . . . . . . . . . 14
⊢ ((𝐺 ∈ GrpOp ∧ 𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋) → (𝑥 = 𝑦 ↔ (𝑥( /𝑔 ‘𝐺)𝑦) = 𝑊)) |
55 | 54 | biimprd 251 |
. . . . . . . . . . . . 13
⊢ ((𝐺 ∈ GrpOp ∧ 𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋) → ((𝑥( /𝑔 ‘𝐺)𝑦) = 𝑊 → 𝑥 = 𝑦)) |
56 | 55 | 3expb 1122 |
. . . . . . . . . . . 12
⊢ ((𝐺 ∈ GrpOp ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → ((𝑥( /𝑔 ‘𝐺)𝑦) = 𝑊 → 𝑥 = 𝑦)) |
57 | 56 | 3ad2antl1 1187 |
. . . . . . . . . . 11
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → ((𝑥( /𝑔 ‘𝐺)𝑦) = 𝑊 → 𝑥 = 𝑦)) |
58 | 53, 57 | syl5 34 |
. . . . . . . . . 10
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → ((𝑥( /𝑔 ‘𝐺)𝑦) ∈ {𝑊} → 𝑥 = 𝑦)) |
59 | 58 | adantlr 715 |
. . . . . . . . 9
⊢ ((((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (◡𝐹 “ {𝑈}) = {𝑊}) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → ((𝑥( /𝑔 ‘𝐺)𝑦) ∈ {𝑊} → 𝑥 = 𝑦)) |
60 | 52, 59 | sylbid 243 |
. . . . . . . 8
⊢ ((((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (◡𝐹 “ {𝑈}) = {𝑊}) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → ((𝐹‘(𝑥( /𝑔 ‘𝐺)𝑦)) ∈ {𝑈} → 𝑥 = 𝑦)) |
61 | 39, 60 | syl5 34 |
. . . . . . 7
⊢ ((((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (◡𝐹 “ {𝑈}) = {𝑊}) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → ((𝐹‘(𝑥( /𝑔 ‘𝐺)𝑦)) = 𝑈 → 𝑥 = 𝑦)) |
62 | 35, 61 | sylbird 263 |
. . . . . 6
⊢ ((((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (◡𝐹 “ {𝑈}) = {𝑊}) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → (((𝐹‘𝑥)( /𝑔 ‘𝐻)(𝐹‘𝑦)) = 𝑈 → 𝑥 = 𝑦)) |
63 | 31, 62 | sylbid 243 |
. . . . 5
⊢ ((((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (◡𝐹 “ {𝑈}) = {𝑊}) ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → ((𝐹‘𝑥) = (𝐹‘𝑦) → 𝑥 = 𝑦)) |
64 | 63 | ralrimivva 3112 |
. . . 4
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (◡𝐹 “ {𝑈}) = {𝑊}) → ∀𝑥 ∈ 𝑋 ∀𝑦 ∈ 𝑋 ((𝐹‘𝑥) = (𝐹‘𝑦) → 𝑥 = 𝑦)) |
65 | | dff13 7067 |
. . . 4
⊢ (𝐹:𝑋–1-1→𝑌 ↔ (𝐹:𝑋⟶𝑌 ∧ ∀𝑥 ∈ 𝑋 ∀𝑦 ∈ 𝑋 ((𝐹‘𝑥) = (𝐹‘𝑦) → 𝑥 = 𝑦))) |
66 | 22, 64, 65 | sylanbrc 586 |
. . 3
⊢ (((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) ∧ (◡𝐹 “ {𝑈}) = {𝑊}) → 𝐹:𝑋–1-1→𝑌) |
67 | 66 | ex 416 |
. 2
⊢ ((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) → ((◡𝐹 “ {𝑈}) = {𝑊} → 𝐹:𝑋–1-1→𝑌)) |
68 | 21, 67 | impbid 215 |
1
⊢ ((𝐺 ∈ GrpOp ∧ 𝐻 ∈ GrpOp ∧ 𝐹 ∈ (𝐺 GrpOpHom 𝐻)) → (𝐹:𝑋–1-1→𝑌 ↔ (◡𝐹 “ {𝑈}) = {𝑊})) |