| Step | Hyp | Ref
 | Expression | 
| 1 |   | ssrab2 3268 | 
. . 3
⊢ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴} ⊆ ℂ | 
| 2 | 1 | a1i 9 | 
. 2
⊢ (𝐴 ∈ ℂ → {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴} ⊆ ℂ) | 
| 3 |   | breq1 4036 | 
. . . . . . . . . 10
⊢ (𝑤 = 𝑥 → (𝑤 # 𝐴 ↔ 𝑥 # 𝐴)) | 
| 4 | 3 | elrab 2920 | 
. . . . . . . . 9
⊢ (𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴} ↔ (𝑥 ∈ ℂ ∧ 𝑥 # 𝐴)) | 
| 5 | 4 | biimpi 120 | 
. . . . . . . 8
⊢ (𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴} → (𝑥 ∈ ℂ ∧ 𝑥 # 𝐴)) | 
| 6 | 5 | adantl 277 | 
. . . . . . 7
⊢ ((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) → (𝑥 ∈ ℂ ∧ 𝑥 # 𝐴)) | 
| 7 | 6 | simpld 112 | 
. . . . . 6
⊢ ((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) → 𝑥 ∈ ℂ) | 
| 8 |   | simpl 109 | 
. . . . . 6
⊢ ((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) → 𝐴 ∈ ℂ) | 
| 9 | 7, 8 | subcld 8337 | 
. . . . 5
⊢ ((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) → (𝑥 − 𝐴) ∈ ℂ) | 
| 10 | 6 | simprd 114 | 
. . . . . 6
⊢ ((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) → 𝑥 # 𝐴) | 
| 11 | 7, 8, 10 | subap0d 8671 | 
. . . . 5
⊢ ((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) → (𝑥 − 𝐴) # 0) | 
| 12 | 9, 11 | absrpclapd 11353 | 
. . . 4
⊢ ((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) → (abs‘(𝑥 − 𝐴)) ∈
ℝ+) | 
| 13 |   | breq1 4036 | 
. . . . . . 7
⊢ (𝑤 = 𝑧 → (𝑤 # 𝐴 ↔ 𝑧 # 𝐴)) | 
| 14 |   | cnxmet 14767 | 
. . . . . . . . . 10
⊢ (abs
∘ − ) ∈ (∞Met‘ℂ) | 
| 15 | 9 | abscld 11346 | 
. . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) → (abs‘(𝑥 − 𝐴)) ∈ ℝ) | 
| 16 | 15 | rexrd 8076 | 
. . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) → (abs‘(𝑥 − 𝐴)) ∈
ℝ*) | 
| 17 |   | elbl 14627 | 
. . . . . . . . . 10
⊢ (((abs
∘ − ) ∈ (∞Met‘ℂ) ∧ 𝑥 ∈ ℂ ∧ (abs‘(𝑥 − 𝐴)) ∈ ℝ*) → (𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴))) ↔ (𝑧 ∈ ℂ ∧ (𝑥(abs ∘ − )𝑧) < (abs‘(𝑥 − 𝐴))))) | 
| 18 | 14, 7, 16, 17 | mp3an2i 1353 | 
. . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) → (𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴))) ↔ (𝑧 ∈ ℂ ∧ (𝑥(abs ∘ − )𝑧) < (abs‘(𝑥 − 𝐴))))) | 
| 19 | 18 | biimpa 296 | 
. . . . . . . 8
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) → (𝑧 ∈ ℂ ∧ (𝑥(abs ∘ − )𝑧) < (abs‘(𝑥 − 𝐴)))) | 
| 20 | 19 | simpld 112 | 
. . . . . . 7
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) → 𝑧 ∈
ℂ) | 
| 21 | 8 | adantr 276 | 
. . . . . . . . . . . 12
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) → 𝐴 ∈
ℂ) | 
| 22 | 20, 21 | subcld 8337 | 
. . . . . . . . . . 11
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) → (𝑧 − 𝐴) ∈ ℂ) | 
| 23 | 22 | abscld 11346 | 
. . . . . . . . . 10
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) →
(abs‘(𝑧 − 𝐴)) ∈
ℝ) | 
| 24 | 7 | adantr 276 | 
. . . . . . . . . . . . . 14
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) → 𝑥 ∈
ℂ) | 
| 25 | 24, 20 | subcld 8337 | 
. . . . . . . . . . . . 13
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) → (𝑥 − 𝑧) ∈ ℂ) | 
| 26 | 25 | abscld 11346 | 
. . . . . . . . . . . 12
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) →
(abs‘(𝑥 − 𝑧)) ∈
ℝ) | 
| 27 | 15 | adantr 276 | 
. . . . . . . . . . . 12
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) →
(abs‘(𝑥 − 𝐴)) ∈
ℝ) | 
| 28 | 26, 23 | readdcld 8056 | 
. . . . . . . . . . . 12
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) →
((abs‘(𝑥 −
𝑧)) + (abs‘(𝑧 − 𝐴))) ∈ ℝ) | 
| 29 |   | eqid 2196 | 
. . . . . . . . . . . . . . 15
⊢ (abs
∘ − ) = (abs ∘ − ) | 
| 30 | 29 | cnmetdval 14765 | 
. . . . . . . . . . . . . 14
⊢ ((𝑥 ∈ ℂ ∧ 𝑧 ∈ ℂ) → (𝑥(abs ∘ − )𝑧) = (abs‘(𝑥 − 𝑧))) | 
| 31 | 24, 20, 30 | syl2anc 411 | 
. . . . . . . . . . . . 13
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) → (𝑥(abs ∘ − )𝑧) = (abs‘(𝑥 − 𝑧))) | 
| 32 | 19 | simprd 114 | 
. . . . . . . . . . . . 13
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) → (𝑥(abs ∘ − )𝑧) < (abs‘(𝑥 − 𝐴))) | 
| 33 | 31, 32 | eqbrtrrd 4057 | 
. . . . . . . . . . . 12
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) →
(abs‘(𝑥 − 𝑧)) < (abs‘(𝑥 − 𝐴))) | 
| 34 | 24, 21, 20 | abs3difd 11365 | 
. . . . . . . . . . . 12
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) →
(abs‘(𝑥 − 𝐴)) ≤ ((abs‘(𝑥 − 𝑧)) + (abs‘(𝑧 − 𝐴)))) | 
| 35 | 26, 27, 28, 33, 34 | ltletrd 8450 | 
. . . . . . . . . . 11
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) →
(abs‘(𝑥 − 𝑧)) < ((abs‘(𝑥 − 𝑧)) + (abs‘(𝑧 − 𝐴)))) | 
| 36 | 23, 26 | ltaddposd 8556 | 
. . . . . . . . . . 11
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) → (0 <
(abs‘(𝑧 − 𝐴)) ↔ (abs‘(𝑥 − 𝑧)) < ((abs‘(𝑥 − 𝑧)) + (abs‘(𝑧 − 𝐴))))) | 
| 37 | 35, 36 | mpbird 167 | 
. . . . . . . . . 10
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) → 0 <
(abs‘(𝑧 − 𝐴))) | 
| 38 | 23, 37 | gt0ap0d 8656 | 
. . . . . . . . 9
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) →
(abs‘(𝑧 − 𝐴)) # 0) | 
| 39 |   | abs00ap 11227 | 
. . . . . . . . . 10
⊢ ((𝑧 − 𝐴) ∈ ℂ → ((abs‘(𝑧 − 𝐴)) # 0 ↔ (𝑧 − 𝐴) # 0)) | 
| 40 | 22, 39 | syl 14 | 
. . . . . . . . 9
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) →
((abs‘(𝑧 −
𝐴)) # 0 ↔ (𝑧 − 𝐴) # 0)) | 
| 41 | 38, 40 | mpbid 147 | 
. . . . . . . 8
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) → (𝑧 − 𝐴) # 0) | 
| 42 |   | subap0 8670 | 
. . . . . . . . 9
⊢ ((𝑧 ∈ ℂ ∧ 𝐴 ∈ ℂ) → ((𝑧 − 𝐴) # 0 ↔ 𝑧 # 𝐴)) | 
| 43 | 20, 21, 42 | syl2anc 411 | 
. . . . . . . 8
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) → ((𝑧 − 𝐴) # 0 ↔ 𝑧 # 𝐴)) | 
| 44 | 41, 43 | mpbid 147 | 
. . . . . . 7
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) → 𝑧 # 𝐴) | 
| 45 | 13, 20, 44 | elrabd 2922 | 
. . . . . 6
⊢ (((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) ∧ 𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) → 𝑧 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) | 
| 46 | 45 | ex 115 | 
. . . . 5
⊢ ((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) → (𝑧 ∈ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴))) → 𝑧 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴})) | 
| 47 | 46 | ssrdv 3189 | 
. . . 4
⊢ ((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) → (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴))) ⊆ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) | 
| 48 |   | oveq2 5930 | 
. . . . . 6
⊢ (𝑟 = (abs‘(𝑥 − 𝐴)) → (𝑥(ball‘(abs ∘ − ))𝑟) = (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴)))) | 
| 49 | 48 | sseq1d 3212 | 
. . . . 5
⊢ (𝑟 = (abs‘(𝑥 − 𝐴)) → ((𝑥(ball‘(abs ∘ − ))𝑟) ⊆ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴} ↔ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴))) ⊆ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴})) | 
| 50 | 49 | rspcev 2868 | 
. . . 4
⊢
(((abs‘(𝑥
− 𝐴)) ∈
ℝ+ ∧ (𝑥(ball‘(abs ∘ −
))(abs‘(𝑥 −
𝐴))) ⊆ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) → ∃𝑟 ∈ ℝ+ (𝑥(ball‘(abs ∘ −
))𝑟) ⊆ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) | 
| 51 | 12, 47, 50 | syl2anc 411 | 
. . 3
⊢ ((𝐴 ∈ ℂ ∧ 𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) → ∃𝑟 ∈ ℝ+ (𝑥(ball‘(abs ∘ −
))𝑟) ⊆ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) | 
| 52 | 51 | ralrimiva 2570 | 
. 2
⊢ (𝐴 ∈ ℂ →
∀𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}∃𝑟 ∈ ℝ+ (𝑥(ball‘(abs ∘ −
))𝑟) ⊆ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}) | 
| 53 |   | eqid 2196 | 
. . . 4
⊢
(MetOpen‘(abs ∘ − )) = (MetOpen‘(abs ∘
− )) | 
| 54 | 53 | elmopn2 14685 | 
. . 3
⊢ ((abs
∘ − ) ∈ (∞Met‘ℂ) → ({𝑤 ∈ ℂ ∣ 𝑤 # 𝐴} ∈ (MetOpen‘(abs ∘ −
)) ↔ ({𝑤 ∈
ℂ ∣ 𝑤 # 𝐴} ⊆ ℂ ∧
∀𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}∃𝑟 ∈ ℝ+ (𝑥(ball‘(abs ∘ −
))𝑟) ⊆ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}))) | 
| 55 | 14, 54 | ax-mp 5 | 
. 2
⊢ ({𝑤 ∈ ℂ ∣ 𝑤 # 𝐴} ∈ (MetOpen‘(abs ∘ −
)) ↔ ({𝑤 ∈
ℂ ∣ 𝑤 # 𝐴} ⊆ ℂ ∧
∀𝑥 ∈ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴}∃𝑟 ∈ ℝ+ (𝑥(ball‘(abs ∘ −
))𝑟) ⊆ {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴})) | 
| 56 | 2, 52, 55 | sylanbrc 417 | 
1
⊢ (𝐴 ∈ ℂ → {𝑤 ∈ ℂ ∣ 𝑤 # 𝐴} ∈ (MetOpen‘(abs ∘ −
))) |