| Step | Hyp | Ref
 | Expression | 
| 1 |   | iooref1o.f | 
. . 3
⊢ 𝐹 = (𝑥 ∈ ℝ ↦ (1 / (1 +
(exp‘𝑥)))) | 
| 2 |   | 1rp 9732 | 
. . . . . . . . 9
⊢ 1 ∈
ℝ+ | 
| 3 | 2 | a1i 9 | 
. . . . . . . 8
⊢ (𝑥 ∈ ℝ → 1 ∈
ℝ+) | 
| 4 |   | rpefcl 11850 | 
. . . . . . . 8
⊢ (𝑥 ∈ ℝ →
(exp‘𝑥) ∈
ℝ+) | 
| 5 | 3, 4 | rpaddcld 9787 | 
. . . . . . 7
⊢ (𝑥 ∈ ℝ → (1 +
(exp‘𝑥)) ∈
ℝ+) | 
| 6 | 5 | rpreccld 9782 | 
. . . . . 6
⊢ (𝑥 ∈ ℝ → (1 / (1 +
(exp‘𝑥))) ∈
ℝ+) | 
| 7 | 6 | rpred 9771 | 
. . . . 5
⊢ (𝑥 ∈ ℝ → (1 / (1 +
(exp‘𝑥))) ∈
ℝ) | 
| 8 | 6 | rpgt0d 9774 | 
. . . . 5
⊢ (𝑥 ∈ ℝ → 0 < (1
/ (1 + (exp‘𝑥)))) | 
| 9 |   | 1red 8041 | 
. . . . . . 7
⊢ (𝑥 ∈ ℝ → 1 ∈
ℝ) | 
| 10 | 9, 4 | ltaddrpd 9805 | 
. . . . . 6
⊢ (𝑥 ∈ ℝ → 1 < (1
+ (exp‘𝑥))) | 
| 11 | 5 | recgt1d 9786 | 
. . . . . 6
⊢ (𝑥 ∈ ℝ → (1 <
(1 + (exp‘𝑥)) ↔
(1 / (1 + (exp‘𝑥)))
< 1)) | 
| 12 | 10, 11 | mpbid 147 | 
. . . . 5
⊢ (𝑥 ∈ ℝ → (1 / (1 +
(exp‘𝑥))) <
1) | 
| 13 |   | 0xr 8073 | 
. . . . . 6
⊢ 0 ∈
ℝ* | 
| 14 |   | 1re 8025 | 
. . . . . . 7
⊢ 1 ∈
ℝ | 
| 15 | 14 | rexri 8084 | 
. . . . . 6
⊢ 1 ∈
ℝ* | 
| 16 |   | elioo2 9996 | 
. . . . . 6
⊢ ((0
∈ ℝ* ∧ 1 ∈ ℝ*) → ((1 / (1
+ (exp‘𝑥))) ∈
(0(,)1) ↔ ((1 / (1 + (exp‘𝑥))) ∈ ℝ ∧ 0 < (1 / (1 +
(exp‘𝑥))) ∧ (1 /
(1 + (exp‘𝑥))) <
1))) | 
| 17 | 13, 15, 16 | mp2an 426 | 
. . . . 5
⊢ ((1 / (1
+ (exp‘𝑥))) ∈
(0(,)1) ↔ ((1 / (1 + (exp‘𝑥))) ∈ ℝ ∧ 0 < (1 / (1 +
(exp‘𝑥))) ∧ (1 /
(1 + (exp‘𝑥))) <
1)) | 
| 18 | 7, 8, 12, 17 | syl3anbrc 1183 | 
. . . 4
⊢ (𝑥 ∈ ℝ → (1 / (1 +
(exp‘𝑥))) ∈
(0(,)1)) | 
| 19 | 18 | adantl 277 | 
. . 3
⊢
((⊤ ∧ 𝑥
∈ ℝ) → (1 / (1 + (exp‘𝑥))) ∈ (0(,)1)) | 
| 20 |   | elioore 9987 | 
. . . . . . . . . 10
⊢ (𝑦 ∈ (0(,)1) → 𝑦 ∈
ℝ) | 
| 21 |   | eliooord 10003 | 
. . . . . . . . . . 11
⊢ (𝑦 ∈ (0(,)1) → (0 <
𝑦 ∧ 𝑦 < 1)) | 
| 22 | 21 | simpld 112 | 
. . . . . . . . . 10
⊢ (𝑦 ∈ (0(,)1) → 0 <
𝑦) | 
| 23 | 20, 22 | elrpd 9768 | 
. . . . . . . . 9
⊢ (𝑦 ∈ (0(,)1) → 𝑦 ∈
ℝ+) | 
| 24 | 23 | rpreccld 9782 | 
. . . . . . . 8
⊢ (𝑦 ∈ (0(,)1) → (1 /
𝑦) ∈
ℝ+) | 
| 25 | 24 | rpred 9771 | 
. . . . . . 7
⊢ (𝑦 ∈ (0(,)1) → (1 /
𝑦) ∈
ℝ) | 
| 26 |   | 1red 8041 | 
. . . . . . 7
⊢ (𝑦 ∈ (0(,)1) → 1 ∈
ℝ) | 
| 27 | 25, 26 | resubcld 8407 | 
. . . . . 6
⊢ (𝑦 ∈ (0(,)1) → ((1 /
𝑦) − 1) ∈
ℝ) | 
| 28 | 21 | simprd 114 | 
. . . . . . . 8
⊢ (𝑦 ∈ (0(,)1) → 𝑦 < 1) | 
| 29 | 23 | reclt1d 9785 | 
. . . . . . . 8
⊢ (𝑦 ∈ (0(,)1) → (𝑦 < 1 ↔ 1 < (1 / 𝑦))) | 
| 30 | 28, 29 | mpbid 147 | 
. . . . . . 7
⊢ (𝑦 ∈ (0(,)1) → 1 < (1
/ 𝑦)) | 
| 31 | 26, 25 | posdifd 8559 | 
. . . . . . 7
⊢ (𝑦 ∈ (0(,)1) → (1 <
(1 / 𝑦) ↔ 0 < ((1 /
𝑦) −
1))) | 
| 32 | 30, 31 | mpbid 147 | 
. . . . . 6
⊢ (𝑦 ∈ (0(,)1) → 0 <
((1 / 𝑦) −
1)) | 
| 33 | 27, 32 | elrpd 9768 | 
. . . . 5
⊢ (𝑦 ∈ (0(,)1) → ((1 /
𝑦) − 1) ∈
ℝ+) | 
| 34 | 33 | relogcld 15118 | 
. . . 4
⊢ (𝑦 ∈ (0(,)1) →
(log‘((1 / 𝑦) −
1)) ∈ ℝ) | 
| 35 | 34 | adantl 277 | 
. . 3
⊢
((⊤ ∧ 𝑦
∈ (0(,)1)) → (log‘((1 / 𝑦) − 1)) ∈
ℝ) | 
| 36 |   | 1cnd 8042 | 
. . . . . . 7
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → 1 ∈
ℂ) | 
| 37 | 4 | adantr 276 | 
. . . . . . . . 9
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) →
(exp‘𝑥) ∈
ℝ+) | 
| 38 | 37 | rpcnd 9773 | 
. . . . . . . 8
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) →
(exp‘𝑥) ∈
ℂ) | 
| 39 | 36, 38 | addcld 8046 | 
. . . . . . 7
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → (1 +
(exp‘𝑥)) ∈
ℂ) | 
| 40 | 23 | adantl 277 | 
. . . . . . . 8
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → 𝑦 ∈
ℝ+) | 
| 41 | 40 | rpcnd 9773 | 
. . . . . . 7
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → 𝑦 ∈
ℂ) | 
| 42 | 40 | rpap0d 9777 | 
. . . . . . 7
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → 𝑦 # 0) | 
| 43 | 36, 39, 41, 42 | divmulap2d 8851 | 
. . . . . 6
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → ((1 /
𝑦) = (1 + (exp‘𝑥)) ↔ 1 = (𝑦 · (1 + (exp‘𝑥))))) | 
| 44 | 24 | adantl 277 | 
. . . . . . . . . 10
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → (1 /
𝑦) ∈
ℝ+) | 
| 45 | 44 | rpcnd 9773 | 
. . . . . . . . 9
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → (1 /
𝑦) ∈
ℂ) | 
| 46 | 36, 38, 45 | addrsub 8397 | 
. . . . . . . 8
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → ((1 +
(exp‘𝑥)) = (1 / 𝑦) ↔ (exp‘𝑥) = ((1 / 𝑦) − 1))) | 
| 47 | 33 | adantl 277 | 
. . . . . . . . . 10
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → ((1 /
𝑦) − 1) ∈
ℝ+) | 
| 48 | 47 | reeflogd 15119 | 
. . . . . . . . 9
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) →
(exp‘(log‘((1 / 𝑦) − 1))) = ((1 / 𝑦) − 1)) | 
| 49 | 48 | eqeq2d 2208 | 
. . . . . . . 8
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) →
((exp‘𝑥) =
(exp‘(log‘((1 / 𝑦) − 1))) ↔ (exp‘𝑥) = ((1 / 𝑦) − 1))) | 
| 50 |   | reef11 11864 | 
. . . . . . . . 9
⊢ ((𝑥 ∈ ℝ ∧
(log‘((1 / 𝑦) −
1)) ∈ ℝ) → ((exp‘𝑥) = (exp‘(log‘((1 / 𝑦) − 1))) ↔ 𝑥 = (log‘((1 / 𝑦) − 1)))) | 
| 51 | 34, 50 | sylan2 286 | 
. . . . . . . 8
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) →
((exp‘𝑥) =
(exp‘(log‘((1 / 𝑦) − 1))) ↔ 𝑥 = (log‘((1 / 𝑦) − 1)))) | 
| 52 | 46, 49, 51 | 3bitr2rd 217 | 
. . . . . . 7
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → (𝑥 = (log‘((1 / 𝑦) − 1)) ↔ (1 +
(exp‘𝑥)) = (1 / 𝑦))) | 
| 53 |   | eqcom 2198 | 
. . . . . . 7
⊢ ((1 +
(exp‘𝑥)) = (1 / 𝑦) ↔ (1 / 𝑦) = (1 + (exp‘𝑥))) | 
| 54 | 52, 53 | bitrdi 196 | 
. . . . . 6
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → (𝑥 = (log‘((1 / 𝑦) − 1)) ↔ (1 / 𝑦) = (1 + (exp‘𝑥)))) | 
| 55 | 5 | adantr 276 | 
. . . . . . . 8
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → (1 +
(exp‘𝑥)) ∈
ℝ+) | 
| 56 | 55 | rpap0d 9777 | 
. . . . . . 7
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → (1 +
(exp‘𝑥)) #
0) | 
| 57 | 36, 41, 39, 56 | divmulap3d 8852 | 
. . . . . 6
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → ((1 / (1
+ (exp‘𝑥))) = 𝑦 ↔ 1 = (𝑦 · (1 + (exp‘𝑥))))) | 
| 58 | 43, 54, 57 | 3bitr4d 220 | 
. . . . 5
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → (𝑥 = (log‘((1 / 𝑦) − 1)) ↔ (1 / (1 +
(exp‘𝑥))) = 𝑦)) | 
| 59 |   | eqcom 2198 | 
. . . . 5
⊢ ((1 / (1
+ (exp‘𝑥))) = 𝑦 ↔ 𝑦 = (1 / (1 + (exp‘𝑥)))) | 
| 60 | 58, 59 | bitrdi 196 | 
. . . 4
⊢ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ (0(,)1)) → (𝑥 = (log‘((1 / 𝑦) − 1)) ↔ 𝑦 = (1 / (1 + (exp‘𝑥))))) | 
| 61 | 60 | adantl 277 | 
. . 3
⊢
((⊤ ∧ (𝑥
∈ ℝ ∧ 𝑦
∈ (0(,)1))) → (𝑥
= (log‘((1 / 𝑦)
− 1)) ↔ 𝑦 = (1 /
(1 + (exp‘𝑥))))) | 
| 62 | 1, 19, 35, 61 | f1o2d 6128 | 
. 2
⊢ (⊤
→ 𝐹:ℝ–1-1-onto→(0(,)1)) | 
| 63 | 62 | mptru 1373 | 
1
⊢ 𝐹:ℝ–1-1-onto→(0(,)1) |