Step |
Hyp |
Ref |
Expression |
1 |
|
redvabs.d |
⊢ 𝐷 = ( ℝ ∖ { 0 } ) |
2 |
|
reelprrecn |
⊢ ℝ ∈ { ℝ , ℂ } |
3 |
2
|
a1i |
⊢ ( ⊤ → ℝ ∈ { ℝ , ℂ } ) |
4 |
1
|
eleq2i |
⊢ ( 𝑥 ∈ 𝐷 ↔ 𝑥 ∈ ( ℝ ∖ { 0 } ) ) |
5 |
|
eldifsn |
⊢ ( 𝑥 ∈ ( ℝ ∖ { 0 } ) ↔ ( 𝑥 ∈ ℝ ∧ 𝑥 ≠ 0 ) ) |
6 |
4 5
|
bitri |
⊢ ( 𝑥 ∈ 𝐷 ↔ ( 𝑥 ∈ ℝ ∧ 𝑥 ≠ 0 ) ) |
7 |
6
|
simplbi |
⊢ ( 𝑥 ∈ 𝐷 → 𝑥 ∈ ℝ ) |
8 |
7
|
recnd |
⊢ ( 𝑥 ∈ 𝐷 → 𝑥 ∈ ℂ ) |
9 |
8
|
sqcld |
⊢ ( 𝑥 ∈ 𝐷 → ( 𝑥 ↑ 2 ) ∈ ℂ ) |
10 |
6
|
simprbi |
⊢ ( 𝑥 ∈ 𝐷 → 𝑥 ≠ 0 ) |
11 |
|
sqne0 |
⊢ ( 𝑥 ∈ ℂ → ( ( 𝑥 ↑ 2 ) ≠ 0 ↔ 𝑥 ≠ 0 ) ) |
12 |
8 11
|
syl |
⊢ ( 𝑥 ∈ 𝐷 → ( ( 𝑥 ↑ 2 ) ≠ 0 ↔ 𝑥 ≠ 0 ) ) |
13 |
10 12
|
mpbird |
⊢ ( 𝑥 ∈ 𝐷 → ( 𝑥 ↑ 2 ) ≠ 0 ) |
14 |
9 13
|
logcld |
⊢ ( 𝑥 ∈ 𝐷 → ( log ‘ ( 𝑥 ↑ 2 ) ) ∈ ℂ ) |
15 |
14
|
adantl |
⊢ ( ( ⊤ ∧ 𝑥 ∈ 𝐷 ) → ( log ‘ ( 𝑥 ↑ 2 ) ) ∈ ℂ ) |
16 |
|
ovexd |
⊢ ( ( ⊤ ∧ 𝑥 ∈ 𝐷 ) → ( ( 1 / ( 𝑥 ↑ 2 ) ) · ( 2 · 𝑥 ) ) ∈ V ) |
17 |
|
cnelprrecn |
⊢ ℂ ∈ { ℝ , ℂ } |
18 |
17
|
a1i |
⊢ ( ⊤ → ℂ ∈ { ℝ , ℂ } ) |
19 |
|
incom |
⊢ ( ℝ+ ∩ ( -∞ (,] 0 ) ) = ( ( -∞ (,] 0 ) ∩ ℝ+ ) |
20 |
|
dfrp2 |
⊢ ℝ+ = ( 0 (,) +∞ ) |
21 |
20
|
ineq2i |
⊢ ( ( -∞ (,] 0 ) ∩ ℝ+ ) = ( ( -∞ (,] 0 ) ∩ ( 0 (,) +∞ ) ) |
22 |
|
mnfxr |
⊢ -∞ ∈ ℝ* |
23 |
22
|
a1i |
⊢ ( ⊤ → -∞ ∈ ℝ* ) |
24 |
|
0xr |
⊢ 0 ∈ ℝ* |
25 |
24
|
a1i |
⊢ ( ⊤ → 0 ∈ ℝ* ) |
26 |
|
pnfxr |
⊢ +∞ ∈ ℝ* |
27 |
26
|
a1i |
⊢ ( ⊤ → +∞ ∈ ℝ* ) |
28 |
23 25 27
|
iocioodisjd |
⊢ ( ⊤ → ( ( -∞ (,] 0 ) ∩ ( 0 (,) +∞ ) ) = ∅ ) |
29 |
28
|
mptru |
⊢ ( ( -∞ (,] 0 ) ∩ ( 0 (,) +∞ ) ) = ∅ |
30 |
19 21 29
|
3eqtri |
⊢ ( ℝ+ ∩ ( -∞ (,] 0 ) ) = ∅ |
31 |
|
disjdif2 |
⊢ ( ( ℝ+ ∩ ( -∞ (,] 0 ) ) = ∅ → ( ℝ+ ∖ ( -∞ (,] 0 ) ) = ℝ+ ) |
32 |
30 31
|
ax-mp |
⊢ ( ℝ+ ∖ ( -∞ (,] 0 ) ) = ℝ+ |
33 |
|
rpsscn |
⊢ ℝ+ ⊆ ℂ |
34 |
|
ssdif |
⊢ ( ℝ+ ⊆ ℂ → ( ℝ+ ∖ ( -∞ (,] 0 ) ) ⊆ ( ℂ ∖ ( -∞ (,] 0 ) ) ) |
35 |
33 34
|
ax-mp |
⊢ ( ℝ+ ∖ ( -∞ (,] 0 ) ) ⊆ ( ℂ ∖ ( -∞ (,] 0 ) ) |
36 |
32 35
|
eqsstrri |
⊢ ℝ+ ⊆ ( ℂ ∖ ( -∞ (,] 0 ) ) |
37 |
10
|
adantl |
⊢ ( ( ⊤ ∧ 𝑥 ∈ 𝐷 ) → 𝑥 ≠ 0 ) |
38 |
|
sqn0rp |
⊢ ( ( 𝑥 ∈ ℝ ∧ 𝑥 ≠ 0 ) → ( 𝑥 ↑ 2 ) ∈ ℝ+ ) |
39 |
7 37 38
|
syl2an2 |
⊢ ( ( ⊤ ∧ 𝑥 ∈ 𝐷 ) → ( 𝑥 ↑ 2 ) ∈ ℝ+ ) |
40 |
36 39
|
sselid |
⊢ ( ( ⊤ ∧ 𝑥 ∈ 𝐷 ) → ( 𝑥 ↑ 2 ) ∈ ( ℂ ∖ ( -∞ (,] 0 ) ) ) |
41 |
|
ovexd |
⊢ ( ( ⊤ ∧ 𝑥 ∈ 𝐷 ) → ( 2 · 𝑥 ) ∈ V ) |
42 |
|
eldifi |
⊢ ( 𝑦 ∈ ( ℂ ∖ ( -∞ (,] 0 ) ) → 𝑦 ∈ ℂ ) |
43 |
|
eldifn |
⊢ ( 𝑦 ∈ ( ℂ ∖ ( -∞ (,] 0 ) ) → ¬ 𝑦 ∈ ( -∞ (,] 0 ) ) |
44 |
|
mnflt0 |
⊢ -∞ < 0 |
45 |
|
0le0 |
⊢ 0 ≤ 0 |
46 |
|
elioc1 |
⊢ ( ( -∞ ∈ ℝ* ∧ 0 ∈ ℝ* ) → ( 0 ∈ ( -∞ (,] 0 ) ↔ ( 0 ∈ ℝ* ∧ -∞ < 0 ∧ 0 ≤ 0 ) ) ) |
47 |
22 24 46
|
mp2an |
⊢ ( 0 ∈ ( -∞ (,] 0 ) ↔ ( 0 ∈ ℝ* ∧ -∞ < 0 ∧ 0 ≤ 0 ) ) |
48 |
24 44 45 47
|
mpbir3an |
⊢ 0 ∈ ( -∞ (,] 0 ) |
49 |
|
eleq1 |
⊢ ( 𝑦 = 0 → ( 𝑦 ∈ ( -∞ (,] 0 ) ↔ 0 ∈ ( -∞ (,] 0 ) ) ) |
50 |
48 49
|
mpbiri |
⊢ ( 𝑦 = 0 → 𝑦 ∈ ( -∞ (,] 0 ) ) |
51 |
50
|
necon3bi |
⊢ ( ¬ 𝑦 ∈ ( -∞ (,] 0 ) → 𝑦 ≠ 0 ) |
52 |
43 51
|
syl |
⊢ ( 𝑦 ∈ ( ℂ ∖ ( -∞ (,] 0 ) ) → 𝑦 ≠ 0 ) |
53 |
42 52
|
logcld |
⊢ ( 𝑦 ∈ ( ℂ ∖ ( -∞ (,] 0 ) ) → ( log ‘ 𝑦 ) ∈ ℂ ) |
54 |
53
|
adantl |
⊢ ( ( ⊤ ∧ 𝑦 ∈ ( ℂ ∖ ( -∞ (,] 0 ) ) ) → ( log ‘ 𝑦 ) ∈ ℂ ) |
55 |
|
ovexd |
⊢ ( ( ⊤ ∧ 𝑦 ∈ ( ℂ ∖ ( -∞ (,] 0 ) ) ) → ( 1 / 𝑦 ) ∈ V ) |
56 |
|
recn |
⊢ ( 𝑥 ∈ ℝ → 𝑥 ∈ ℂ ) |
57 |
56
|
adantl |
⊢ ( ( ⊤ ∧ 𝑥 ∈ ℝ ) → 𝑥 ∈ ℂ ) |
58 |
57
|
sqcld |
⊢ ( ( ⊤ ∧ 𝑥 ∈ ℝ ) → ( 𝑥 ↑ 2 ) ∈ ℂ ) |
59 |
|
ovexd |
⊢ ( ( ⊤ ∧ 𝑥 ∈ ℝ ) → ( 2 · ( 𝑥 ↑ ( 2 − 1 ) ) ) ∈ V ) |
60 |
|
eqid |
⊢ ( TopOpen ‘ ℂfld ) = ( TopOpen ‘ ℂfld ) |
61 |
|
cnopn |
⊢ ℂ ∈ ( TopOpen ‘ ℂfld ) |
62 |
61
|
a1i |
⊢ ( ⊤ → ℂ ∈ ( TopOpen ‘ ℂfld ) ) |
63 |
|
ax-resscn |
⊢ ℝ ⊆ ℂ |
64 |
|
dfss2 |
⊢ ( ℝ ⊆ ℂ ↔ ( ℝ ∩ ℂ ) = ℝ ) |
65 |
63 64
|
mpbi |
⊢ ( ℝ ∩ ℂ ) = ℝ |
66 |
65
|
a1i |
⊢ ( ⊤ → ( ℝ ∩ ℂ ) = ℝ ) |
67 |
|
sqcl |
⊢ ( 𝑥 ∈ ℂ → ( 𝑥 ↑ 2 ) ∈ ℂ ) |
68 |
67
|
adantl |
⊢ ( ( ⊤ ∧ 𝑥 ∈ ℂ ) → ( 𝑥 ↑ 2 ) ∈ ℂ ) |
69 |
|
ovexd |
⊢ ( ( ⊤ ∧ 𝑥 ∈ ℂ ) → ( 2 · ( 𝑥 ↑ ( 2 − 1 ) ) ) ∈ V ) |
70 |
|
2nn |
⊢ 2 ∈ ℕ |
71 |
|
dvexp |
⊢ ( 2 ∈ ℕ → ( ℂ D ( 𝑥 ∈ ℂ ↦ ( 𝑥 ↑ 2 ) ) ) = ( 𝑥 ∈ ℂ ↦ ( 2 · ( 𝑥 ↑ ( 2 − 1 ) ) ) ) ) |
72 |
70 71
|
mp1i |
⊢ ( ⊤ → ( ℂ D ( 𝑥 ∈ ℂ ↦ ( 𝑥 ↑ 2 ) ) ) = ( 𝑥 ∈ ℂ ↦ ( 2 · ( 𝑥 ↑ ( 2 − 1 ) ) ) ) ) |
73 |
60 3 62 66 68 69 72
|
dvmptres3 |
⊢ ( ⊤ → ( ℝ D ( 𝑥 ∈ ℝ ↦ ( 𝑥 ↑ 2 ) ) ) = ( 𝑥 ∈ ℝ ↦ ( 2 · ( 𝑥 ↑ ( 2 − 1 ) ) ) ) ) |
74 |
7
|
ssriv |
⊢ 𝐷 ⊆ ℝ |
75 |
74
|
a1i |
⊢ ( ⊤ → 𝐷 ⊆ ℝ ) |
76 |
60
|
tgioo2 |
⊢ ( topGen ‘ ran (,) ) = ( ( TopOpen ‘ ℂfld ) ↾t ℝ ) |
77 |
|
rehaus |
⊢ ( topGen ‘ ran (,) ) ∈ Haus |
78 |
|
0re |
⊢ 0 ∈ ℝ |
79 |
|
uniretop |
⊢ ℝ = ∪ ( topGen ‘ ran (,) ) |
80 |
79
|
sncld |
⊢ ( ( ( topGen ‘ ran (,) ) ∈ Haus ∧ 0 ∈ ℝ ) → { 0 } ∈ ( Clsd ‘ ( topGen ‘ ran (,) ) ) ) |
81 |
77 78 80
|
mp2an |
⊢ { 0 } ∈ ( Clsd ‘ ( topGen ‘ ran (,) ) ) |
82 |
79
|
cldopn |
⊢ ( { 0 } ∈ ( Clsd ‘ ( topGen ‘ ran (,) ) ) → ( ℝ ∖ { 0 } ) ∈ ( topGen ‘ ran (,) ) ) |
83 |
81 82
|
ax-mp |
⊢ ( ℝ ∖ { 0 } ) ∈ ( topGen ‘ ran (,) ) |
84 |
1 83
|
eqeltri |
⊢ 𝐷 ∈ ( topGen ‘ ran (,) ) |
85 |
84
|
a1i |
⊢ ( ⊤ → 𝐷 ∈ ( topGen ‘ ran (,) ) ) |
86 |
3 58 59 73 75 76 60 85
|
dvmptres |
⊢ ( ⊤ → ( ℝ D ( 𝑥 ∈ 𝐷 ↦ ( 𝑥 ↑ 2 ) ) ) = ( 𝑥 ∈ 𝐷 ↦ ( 2 · ( 𝑥 ↑ ( 2 − 1 ) ) ) ) ) |
87 |
|
2m1e1 |
⊢ ( 2 − 1 ) = 1 |
88 |
87
|
oveq2i |
⊢ ( 𝑥 ↑ ( 2 − 1 ) ) = ( 𝑥 ↑ 1 ) |
89 |
8
|
exp1d |
⊢ ( 𝑥 ∈ 𝐷 → ( 𝑥 ↑ 1 ) = 𝑥 ) |
90 |
88 89
|
eqtrid |
⊢ ( 𝑥 ∈ 𝐷 → ( 𝑥 ↑ ( 2 − 1 ) ) = 𝑥 ) |
91 |
90
|
oveq2d |
⊢ ( 𝑥 ∈ 𝐷 → ( 2 · ( 𝑥 ↑ ( 2 − 1 ) ) ) = ( 2 · 𝑥 ) ) |
92 |
91
|
mpteq2ia |
⊢ ( 𝑥 ∈ 𝐷 ↦ ( 2 · ( 𝑥 ↑ ( 2 − 1 ) ) ) ) = ( 𝑥 ∈ 𝐷 ↦ ( 2 · 𝑥 ) ) |
93 |
86 92
|
eqtrdi |
⊢ ( ⊤ → ( ℝ D ( 𝑥 ∈ 𝐷 ↦ ( 𝑥 ↑ 2 ) ) ) = ( 𝑥 ∈ 𝐷 ↦ ( 2 · 𝑥 ) ) ) |
94 |
|
logf1o |
⊢ log : ( ℂ ∖ { 0 } ) –1-1-onto→ ran log |
95 |
|
f1of |
⊢ ( log : ( ℂ ∖ { 0 } ) –1-1-onto→ ran log → log : ( ℂ ∖ { 0 } ) ⟶ ran log ) |
96 |
94 95
|
mp1i |
⊢ ( ⊤ → log : ( ℂ ∖ { 0 } ) ⟶ ran log ) |
97 |
|
snssi |
⊢ ( 0 ∈ ( -∞ (,] 0 ) → { 0 } ⊆ ( -∞ (,] 0 ) ) |
98 |
48 97
|
ax-mp |
⊢ { 0 } ⊆ ( -∞ (,] 0 ) |
99 |
|
sscon |
⊢ ( { 0 } ⊆ ( -∞ (,] 0 ) → ( ℂ ∖ ( -∞ (,] 0 ) ) ⊆ ( ℂ ∖ { 0 } ) ) |
100 |
98 99
|
mp1i |
⊢ ( ⊤ → ( ℂ ∖ ( -∞ (,] 0 ) ) ⊆ ( ℂ ∖ { 0 } ) ) |
101 |
96 100
|
feqresmpt |
⊢ ( ⊤ → ( log ↾ ( ℂ ∖ ( -∞ (,] 0 ) ) ) = ( 𝑦 ∈ ( ℂ ∖ ( -∞ (,] 0 ) ) ↦ ( log ‘ 𝑦 ) ) ) |
102 |
101
|
oveq2d |
⊢ ( ⊤ → ( ℂ D ( log ↾ ( ℂ ∖ ( -∞ (,] 0 ) ) ) ) = ( ℂ D ( 𝑦 ∈ ( ℂ ∖ ( -∞ (,] 0 ) ) ↦ ( log ‘ 𝑦 ) ) ) ) |
103 |
|
eqid |
⊢ ( ℂ ∖ ( -∞ (,] 0 ) ) = ( ℂ ∖ ( -∞ (,] 0 ) ) |
104 |
103
|
dvlog |
⊢ ( ℂ D ( log ↾ ( ℂ ∖ ( -∞ (,] 0 ) ) ) ) = ( 𝑦 ∈ ( ℂ ∖ ( -∞ (,] 0 ) ) ↦ ( 1 / 𝑦 ) ) |
105 |
102 104
|
eqtr3di |
⊢ ( ⊤ → ( ℂ D ( 𝑦 ∈ ( ℂ ∖ ( -∞ (,] 0 ) ) ↦ ( log ‘ 𝑦 ) ) ) = ( 𝑦 ∈ ( ℂ ∖ ( -∞ (,] 0 ) ) ↦ ( 1 / 𝑦 ) ) ) |
106 |
|
fveq2 |
⊢ ( 𝑦 = ( 𝑥 ↑ 2 ) → ( log ‘ 𝑦 ) = ( log ‘ ( 𝑥 ↑ 2 ) ) ) |
107 |
|
oveq2 |
⊢ ( 𝑦 = ( 𝑥 ↑ 2 ) → ( 1 / 𝑦 ) = ( 1 / ( 𝑥 ↑ 2 ) ) ) |
108 |
3 18 40 41 54 55 93 105 106 107
|
dvmptco |
⊢ ( ⊤ → ( ℝ D ( 𝑥 ∈ 𝐷 ↦ ( log ‘ ( 𝑥 ↑ 2 ) ) ) ) = ( 𝑥 ∈ 𝐷 ↦ ( ( 1 / ( 𝑥 ↑ 2 ) ) · ( 2 · 𝑥 ) ) ) ) |
109 |
|
2cnd |
⊢ ( ⊤ → 2 ∈ ℂ ) |
110 |
|
2ne0 |
⊢ 2 ≠ 0 |
111 |
110
|
a1i |
⊢ ( ⊤ → 2 ≠ 0 ) |
112 |
3 15 16 108 109 111
|
dvmptdivc |
⊢ ( ⊤ → ( ℝ D ( 𝑥 ∈ 𝐷 ↦ ( ( log ‘ ( 𝑥 ↑ 2 ) ) / 2 ) ) ) = ( 𝑥 ∈ 𝐷 ↦ ( ( ( 1 / ( 𝑥 ↑ 2 ) ) · ( 2 · 𝑥 ) ) / 2 ) ) ) |
113 |
112
|
mptru |
⊢ ( ℝ D ( 𝑥 ∈ 𝐷 ↦ ( ( log ‘ ( 𝑥 ↑ 2 ) ) / 2 ) ) ) = ( 𝑥 ∈ 𝐷 ↦ ( ( ( 1 / ( 𝑥 ↑ 2 ) ) · ( 2 · 𝑥 ) ) / 2 ) ) |
114 |
7
|
resqcld |
⊢ ( 𝑥 ∈ 𝐷 → ( 𝑥 ↑ 2 ) ∈ ℝ ) |
115 |
114 13
|
rereccld |
⊢ ( 𝑥 ∈ 𝐷 → ( 1 / ( 𝑥 ↑ 2 ) ) ∈ ℝ ) |
116 |
115
|
recnd |
⊢ ( 𝑥 ∈ 𝐷 → ( 1 / ( 𝑥 ↑ 2 ) ) ∈ ℂ ) |
117 |
|
2cnd |
⊢ ( 𝑥 ∈ 𝐷 → 2 ∈ ℂ ) |
118 |
116 117 8
|
mul12d |
⊢ ( 𝑥 ∈ 𝐷 → ( ( 1 / ( 𝑥 ↑ 2 ) ) · ( 2 · 𝑥 ) ) = ( 2 · ( ( 1 / ( 𝑥 ↑ 2 ) ) · 𝑥 ) ) ) |
119 |
118
|
oveq1d |
⊢ ( 𝑥 ∈ 𝐷 → ( ( ( 1 / ( 𝑥 ↑ 2 ) ) · ( 2 · 𝑥 ) ) / 2 ) = ( ( 2 · ( ( 1 / ( 𝑥 ↑ 2 ) ) · 𝑥 ) ) / 2 ) ) |
120 |
116 8
|
mulcld |
⊢ ( 𝑥 ∈ 𝐷 → ( ( 1 / ( 𝑥 ↑ 2 ) ) · 𝑥 ) ∈ ℂ ) |
121 |
110
|
a1i |
⊢ ( 𝑥 ∈ 𝐷 → 2 ≠ 0 ) |
122 |
120 117 121
|
divcan3d |
⊢ ( 𝑥 ∈ 𝐷 → ( ( 2 · ( ( 1 / ( 𝑥 ↑ 2 ) ) · 𝑥 ) ) / 2 ) = ( ( 1 / ( 𝑥 ↑ 2 ) ) · 𝑥 ) ) |
123 |
8
|
sqvald |
⊢ ( 𝑥 ∈ 𝐷 → ( 𝑥 ↑ 2 ) = ( 𝑥 · 𝑥 ) ) |
124 |
123
|
oveq2d |
⊢ ( 𝑥 ∈ 𝐷 → ( 1 / ( 𝑥 ↑ 2 ) ) = ( 1 / ( 𝑥 · 𝑥 ) ) ) |
125 |
124
|
oveq1d |
⊢ ( 𝑥 ∈ 𝐷 → ( ( 1 / ( 𝑥 ↑ 2 ) ) · 𝑥 ) = ( ( 1 / ( 𝑥 · 𝑥 ) ) · 𝑥 ) ) |
126 |
8 8 10 10
|
recdiv2d |
⊢ ( 𝑥 ∈ 𝐷 → ( ( 1 / 𝑥 ) / 𝑥 ) = ( 1 / ( 𝑥 · 𝑥 ) ) ) |
127 |
126
|
oveq1d |
⊢ ( 𝑥 ∈ 𝐷 → ( ( ( 1 / 𝑥 ) / 𝑥 ) · 𝑥 ) = ( ( 1 / ( 𝑥 · 𝑥 ) ) · 𝑥 ) ) |
128 |
8 10
|
reccld |
⊢ ( 𝑥 ∈ 𝐷 → ( 1 / 𝑥 ) ∈ ℂ ) |
129 |
128 8 10
|
divcan1d |
⊢ ( 𝑥 ∈ 𝐷 → ( ( ( 1 / 𝑥 ) / 𝑥 ) · 𝑥 ) = ( 1 / 𝑥 ) ) |
130 |
125 127 129
|
3eqtr2d |
⊢ ( 𝑥 ∈ 𝐷 → ( ( 1 / ( 𝑥 ↑ 2 ) ) · 𝑥 ) = ( 1 / 𝑥 ) ) |
131 |
119 122 130
|
3eqtrd |
⊢ ( 𝑥 ∈ 𝐷 → ( ( ( 1 / ( 𝑥 ↑ 2 ) ) · ( 2 · 𝑥 ) ) / 2 ) = ( 1 / 𝑥 ) ) |
132 |
131
|
mpteq2ia |
⊢ ( 𝑥 ∈ 𝐷 ↦ ( ( ( 1 / ( 𝑥 ↑ 2 ) ) · ( 2 · 𝑥 ) ) / 2 ) ) = ( 𝑥 ∈ 𝐷 ↦ ( 1 / 𝑥 ) ) |
133 |
113 132
|
eqtri |
⊢ ( ℝ D ( 𝑥 ∈ 𝐷 ↦ ( ( log ‘ ( 𝑥 ↑ 2 ) ) / 2 ) ) ) = ( 𝑥 ∈ 𝐷 ↦ ( 1 / 𝑥 ) ) |