Step |
Hyp |
Ref |
Expression |
1 |
|
brgic |
⊢ ( 𝐺 ≃𝑔 𝐻 ↔ ( 𝐺 GrpIso 𝐻 ) ≠ ∅ ) |
2 |
|
n0 |
⊢ ( ( 𝐺 GrpIso 𝐻 ) ≠ ∅ ↔ ∃ 𝑓 𝑓 ∈ ( 𝐺 GrpIso 𝐻 ) ) |
3 |
|
gimghm |
⊢ ( 𝑓 ∈ ( 𝐺 GrpIso 𝐻 ) → 𝑓 ∈ ( 𝐺 GrpHom 𝐻 ) ) |
4 |
|
eqid |
⊢ ( Base ‘ 𝐺 ) = ( Base ‘ 𝐺 ) |
5 |
|
eqid |
⊢ ( Base ‘ 𝐻 ) = ( Base ‘ 𝐻 ) |
6 |
4 5
|
gimf1o |
⊢ ( 𝑓 ∈ ( 𝐺 GrpIso 𝐻 ) → 𝑓 : ( Base ‘ 𝐺 ) –1-1-onto→ ( Base ‘ 𝐻 ) ) |
7 |
|
f1ofo |
⊢ ( 𝑓 : ( Base ‘ 𝐺 ) –1-1-onto→ ( Base ‘ 𝐻 ) → 𝑓 : ( Base ‘ 𝐺 ) –onto→ ( Base ‘ 𝐻 ) ) |
8 |
6 7
|
syl |
⊢ ( 𝑓 ∈ ( 𝐺 GrpIso 𝐻 ) → 𝑓 : ( Base ‘ 𝐺 ) –onto→ ( Base ‘ 𝐻 ) ) |
9 |
4 5
|
ghmcyg |
⊢ ( ( 𝑓 ∈ ( 𝐺 GrpHom 𝐻 ) ∧ 𝑓 : ( Base ‘ 𝐺 ) –onto→ ( Base ‘ 𝐻 ) ) → ( 𝐺 ∈ CycGrp → 𝐻 ∈ CycGrp ) ) |
10 |
3 8 9
|
syl2anc |
⊢ ( 𝑓 ∈ ( 𝐺 GrpIso 𝐻 ) → ( 𝐺 ∈ CycGrp → 𝐻 ∈ CycGrp ) ) |
11 |
10
|
exlimiv |
⊢ ( ∃ 𝑓 𝑓 ∈ ( 𝐺 GrpIso 𝐻 ) → ( 𝐺 ∈ CycGrp → 𝐻 ∈ CycGrp ) ) |
12 |
2 11
|
sylbi |
⊢ ( ( 𝐺 GrpIso 𝐻 ) ≠ ∅ → ( 𝐺 ∈ CycGrp → 𝐻 ∈ CycGrp ) ) |
13 |
1 12
|
sylbi |
⊢ ( 𝐺 ≃𝑔 𝐻 → ( 𝐺 ∈ CycGrp → 𝐻 ∈ CycGrp ) ) |