| Step | Hyp | Ref
 | Expression | 
| 1 |   | phival 12381 | 
. 2
⊢ (𝑁 ∈ ℕ →
(ϕ‘𝑁) =
(♯‘{𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1})) | 
| 2 |   | phivalfi 12380 | 
. . . . 5
⊢ (𝑁 ∈ ℕ → {𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1} ∈ Fin) | 
| 3 |   | hashcl 10873 | 
. . . . 5
⊢ ({𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1} ∈ Fin →
(♯‘{𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ∈
ℕ0) | 
| 4 | 2, 3 | syl 14 | 
. . . 4
⊢ (𝑁 ∈ ℕ →
(♯‘{𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ∈
ℕ0) | 
| 5 | 4 | nn0zd 9446 | 
. . 3
⊢ (𝑁 ∈ ℕ →
(♯‘{𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ∈ ℤ) | 
| 6 |   | 1z 9352 | 
. . . . 5
⊢ 1 ∈
ℤ | 
| 7 |   | hashsng 10890 | 
. . . . 5
⊢ (1 ∈
ℤ → (♯‘{1}) = 1) | 
| 8 | 6, 7 | ax-mp 5 | 
. . . 4
⊢
(♯‘{1}) = 1 | 
| 9 |   | eluzfz1 10106 | 
. . . . . . . . 9
⊢ (𝑁 ∈
(ℤ≥‘1) → 1 ∈ (1...𝑁)) | 
| 10 |   | nnuz 9637 | 
. . . . . . . . 9
⊢ ℕ =
(ℤ≥‘1) | 
| 11 | 9, 10 | eleq2s 2291 | 
. . . . . . . 8
⊢ (𝑁 ∈ ℕ → 1 ∈
(1...𝑁)) | 
| 12 |   | nnz 9345 | 
. . . . . . . . 9
⊢ (𝑁 ∈ ℕ → 𝑁 ∈
ℤ) | 
| 13 |   | 1gcd 12159 | 
. . . . . . . . 9
⊢ (𝑁 ∈ ℤ → (1 gcd
𝑁) = 1) | 
| 14 | 12, 13 | syl 14 | 
. . . . . . . 8
⊢ (𝑁 ∈ ℕ → (1 gcd
𝑁) = 1) | 
| 15 |   | oveq1 5929 | 
. . . . . . . . . 10
⊢ (𝑥 = 1 → (𝑥 gcd 𝑁) = (1 gcd 𝑁)) | 
| 16 | 15 | eqeq1d 2205 | 
. . . . . . . . 9
⊢ (𝑥 = 1 → ((𝑥 gcd 𝑁) = 1 ↔ (1 gcd 𝑁) = 1)) | 
| 17 | 16 | elrab 2920 | 
. . . . . . . 8
⊢ (1 ∈
{𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1} ↔ (1 ∈ (1...𝑁) ∧ (1 gcd 𝑁) = 1)) | 
| 18 | 11, 14, 17 | sylanbrc 417 | 
. . . . . . 7
⊢ (𝑁 ∈ ℕ → 1 ∈
{𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) | 
| 19 | 18 | snssd 3767 | 
. . . . . 6
⊢ (𝑁 ∈ ℕ → {1}
⊆ {𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) | 
| 20 |   | ssdomg 6837 | 
. . . . . 6
⊢ ({𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1} ∈ Fin → ({1} ⊆ {𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1} → {1} ≼ {𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1})) | 
| 21 | 2, 19, 20 | sylc 62 | 
. . . . 5
⊢ (𝑁 ∈ ℕ → {1}
≼ {𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) | 
| 22 |   | 1nn 9001 | 
. . . . . . 7
⊢ 1 ∈
ℕ | 
| 23 |   | snfig 6873 | 
. . . . . . 7
⊢ (1 ∈
ℕ → {1} ∈ Fin) | 
| 24 | 22, 23 | ax-mp 5 | 
. . . . . 6
⊢ {1}
∈ Fin | 
| 25 |   | fihashdom 10895 | 
. . . . . 6
⊢ (({1}
∈ Fin ∧ {𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1} ∈ Fin) →
((♯‘{1}) ≤ (♯‘{𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ↔ {1} ≼ {𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1})) | 
| 26 | 24, 2, 25 | sylancr 414 | 
. . . . 5
⊢ (𝑁 ∈ ℕ →
((♯‘{1}) ≤ (♯‘{𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ↔ {1} ≼ {𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1})) | 
| 27 | 21, 26 | mpbird 167 | 
. . . 4
⊢ (𝑁 ∈ ℕ →
(♯‘{1}) ≤ (♯‘{𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1})) | 
| 28 | 8, 27 | eqbrtrrid 4069 | 
. . 3
⊢ (𝑁 ∈ ℕ → 1 ≤
(♯‘{𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1})) | 
| 29 |   | 1zzd 9353 | 
. . . . . . 7
⊢ (𝑁 ∈ ℕ → 1 ∈
ℤ) | 
| 30 | 29, 12 | fzfigd 10523 | 
. . . . . 6
⊢ (𝑁 ∈ ℕ →
(1...𝑁) ∈
Fin) | 
| 31 |   | ssrab2 3268 | 
. . . . . 6
⊢ {𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1} ⊆ (1...𝑁) | 
| 32 |   | ssdomg 6837 | 
. . . . . 6
⊢
((1...𝑁) ∈ Fin
→ ({𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1} ⊆ (1...𝑁) → {𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1} ≼ (1...𝑁))) | 
| 33 | 30, 31, 32 | mpisyl 1457 | 
. . . . 5
⊢ (𝑁 ∈ ℕ → {𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1} ≼ (1...𝑁)) | 
| 34 |   | fihashdom 10895 | 
. . . . . 6
⊢ (({𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1} ∈ Fin ∧ (1...𝑁) ∈ Fin) →
((♯‘{𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ≤ (♯‘(1...𝑁)) ↔ {𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1} ≼ (1...𝑁))) | 
| 35 | 2, 30, 34 | syl2anc 411 | 
. . . . 5
⊢ (𝑁 ∈ ℕ →
((♯‘{𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ≤ (♯‘(1...𝑁)) ↔ {𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1} ≼ (1...𝑁))) | 
| 36 | 33, 35 | mpbird 167 | 
. . . 4
⊢ (𝑁 ∈ ℕ →
(♯‘{𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ≤ (♯‘(1...𝑁))) | 
| 37 |   | nnnn0 9256 | 
. . . . 5
⊢ (𝑁 ∈ ℕ → 𝑁 ∈
ℕ0) | 
| 38 |   | hashfz1 10875 | 
. . . . 5
⊢ (𝑁 ∈ ℕ0
→ (♯‘(1...𝑁)) = 𝑁) | 
| 39 | 37, 38 | syl 14 | 
. . . 4
⊢ (𝑁 ∈ ℕ →
(♯‘(1...𝑁)) =
𝑁) | 
| 40 | 36, 39 | breqtrd 4059 | 
. . 3
⊢ (𝑁 ∈ ℕ →
(♯‘{𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ≤ 𝑁) | 
| 41 |   | elfz1 10088 | 
. . . 4
⊢ ((1
∈ ℤ ∧ 𝑁
∈ ℤ) → ((♯‘{𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ∈ (1...𝑁) ↔ ((♯‘{𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ∈ ℤ ∧ 1 ≤
(♯‘{𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ∧ (♯‘{𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ≤ 𝑁))) | 
| 42 | 6, 12, 41 | sylancr 414 | 
. . 3
⊢ (𝑁 ∈ ℕ →
((♯‘{𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ∈ (1...𝑁) ↔ ((♯‘{𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ∈ ℤ ∧ 1 ≤
(♯‘{𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ∧ (♯‘{𝑥 ∈ (1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ≤ 𝑁))) | 
| 43 | 5, 28, 40, 42 | mpbir3and 1182 | 
. 2
⊢ (𝑁 ∈ ℕ →
(♯‘{𝑥 ∈
(1...𝑁) ∣ (𝑥 gcd 𝑁) = 1}) ∈ (1...𝑁)) | 
| 44 | 1, 43 | eqeltrd 2273 | 
1
⊢ (𝑁 ∈ ℕ →
(ϕ‘𝑁) ∈
(1...𝑁)) |