Proof of Theorem max0addsup
| Step | Hyp | Ref
 | Expression | 
| 1 |   | 0re 8026 | 
. . . . . 6
⊢ 0 ∈
ℝ | 
| 2 |   | maxabs 11374 | 
. . . . . 6
⊢ ((𝐴 ∈ ℝ ∧ 0 ∈
ℝ) → sup({𝐴, 0},
ℝ, < ) = (((𝐴 + 0)
+ (abs‘(𝐴 −
0))) / 2)) | 
| 3 | 1, 2 | mpan2 425 | 
. . . . 5
⊢ (𝐴 ∈ ℝ →
sup({𝐴, 0}, ℝ, < )
= (((𝐴 + 0) +
(abs‘(𝐴 − 0)))
/ 2)) | 
| 4 |   | recn 8012 | 
. . . . . . . 8
⊢ (𝐴 ∈ ℝ → 𝐴 ∈
ℂ) | 
| 5 | 4 | addridd 8175 | 
. . . . . . 7
⊢ (𝐴 ∈ ℝ → (𝐴 + 0) = 𝐴) | 
| 6 | 4 | subid1d 8326 | 
. . . . . . . 8
⊢ (𝐴 ∈ ℝ → (𝐴 − 0) = 𝐴) | 
| 7 | 6 | fveq2d 5562 | 
. . . . . . 7
⊢ (𝐴 ∈ ℝ →
(abs‘(𝐴 − 0)) =
(abs‘𝐴)) | 
| 8 | 5, 7 | oveq12d 5940 | 
. . . . . 6
⊢ (𝐴 ∈ ℝ → ((𝐴 + 0) + (abs‘(𝐴 − 0))) = (𝐴 + (abs‘𝐴))) | 
| 9 | 8 | oveq1d 5937 | 
. . . . 5
⊢ (𝐴 ∈ ℝ → (((𝐴 + 0) + (abs‘(𝐴 − 0))) / 2) = ((𝐴 + (abs‘𝐴)) / 2)) | 
| 10 | 3, 9 | eqtrd 2229 | 
. . . 4
⊢ (𝐴 ∈ ℝ →
sup({𝐴, 0}, ℝ, < )
= ((𝐴 + (abs‘𝐴)) / 2)) | 
| 11 |   | renegcl 8287 | 
. . . . . 6
⊢ (𝐴 ∈ ℝ → -𝐴 ∈
ℝ) | 
| 12 |   | maxabs 11374 | 
. . . . . 6
⊢ ((-𝐴 ∈ ℝ ∧ 0 ∈
ℝ) → sup({-𝐴,
0}, ℝ, < ) = (((-𝐴
+ 0) + (abs‘(-𝐴
− 0))) / 2)) | 
| 13 | 11, 1, 12 | sylancl 413 | 
. . . . 5
⊢ (𝐴 ∈ ℝ →
sup({-𝐴, 0}, ℝ, <
) = (((-𝐴 + 0) +
(abs‘(-𝐴 − 0)))
/ 2)) | 
| 14 | 11 | recnd 8055 | 
. . . . . . . 8
⊢ (𝐴 ∈ ℝ → -𝐴 ∈
ℂ) | 
| 15 | 14 | addridd 8175 | 
. . . . . . 7
⊢ (𝐴 ∈ ℝ → (-𝐴 + 0) = -𝐴) | 
| 16 | 14 | subid1d 8326 | 
. . . . . . . . 9
⊢ (𝐴 ∈ ℝ → (-𝐴 − 0) = -𝐴) | 
| 17 | 16 | fveq2d 5562 | 
. . . . . . . 8
⊢ (𝐴 ∈ ℝ →
(abs‘(-𝐴 − 0))
= (abs‘-𝐴)) | 
| 18 | 4 | absnegd 11354 | 
. . . . . . . 8
⊢ (𝐴 ∈ ℝ →
(abs‘-𝐴) =
(abs‘𝐴)) | 
| 19 | 17, 18 | eqtrd 2229 | 
. . . . . . 7
⊢ (𝐴 ∈ ℝ →
(abs‘(-𝐴 − 0))
= (abs‘𝐴)) | 
| 20 | 15, 19 | oveq12d 5940 | 
. . . . . 6
⊢ (𝐴 ∈ ℝ → ((-𝐴 + 0) + (abs‘(-𝐴 − 0))) = (-𝐴 + (abs‘𝐴))) | 
| 21 | 20 | oveq1d 5937 | 
. . . . 5
⊢ (𝐴 ∈ ℝ → (((-𝐴 + 0) + (abs‘(-𝐴 − 0))) / 2) = ((-𝐴 + (abs‘𝐴)) / 2)) | 
| 22 | 13, 21 | eqtrd 2229 | 
. . . 4
⊢ (𝐴 ∈ ℝ →
sup({-𝐴, 0}, ℝ, <
) = ((-𝐴 + (abs‘𝐴)) / 2)) | 
| 23 | 10, 22 | oveq12d 5940 | 
. . 3
⊢ (𝐴 ∈ ℝ →
(sup({𝐴, 0}, ℝ, <
) + sup({-𝐴, 0}, ℝ,
< )) = (((𝐴 +
(abs‘𝐴)) / 2) +
((-𝐴 + (abs‘𝐴)) / 2))) | 
| 24 | 4 | abscld 11346 | 
. . . . . 6
⊢ (𝐴 ∈ ℝ →
(abs‘𝐴) ∈
ℝ) | 
| 25 | 24 | recnd 8055 | 
. . . . 5
⊢ (𝐴 ∈ ℝ →
(abs‘𝐴) ∈
ℂ) | 
| 26 | 4, 25 | addcld 8046 | 
. . . 4
⊢ (𝐴 ∈ ℝ → (𝐴 + (abs‘𝐴)) ∈ ℂ) | 
| 27 | 14, 25 | addcld 8046 | 
. . . 4
⊢ (𝐴 ∈ ℝ → (-𝐴 + (abs‘𝐴)) ∈ ℂ) | 
| 28 |   | 2cnd 9063 | 
. . . 4
⊢ (𝐴 ∈ ℝ → 2 ∈
ℂ) | 
| 29 |   | 2ap0 9083 | 
. . . . 5
⊢ 2 #
0 | 
| 30 | 29 | a1i 9 | 
. . . 4
⊢ (𝐴 ∈ ℝ → 2 #
0) | 
| 31 | 26, 27, 28, 30 | divdirapd 8856 | 
. . 3
⊢ (𝐴 ∈ ℝ → (((𝐴 + (abs‘𝐴)) + (-𝐴 + (abs‘𝐴))) / 2) = (((𝐴 + (abs‘𝐴)) / 2) + ((-𝐴 + (abs‘𝐴)) / 2))) | 
| 32 | 4, 25, 14, 25 | add4d 8195 | 
. . . . 5
⊢ (𝐴 ∈ ℝ → ((𝐴 + (abs‘𝐴)) + (-𝐴 + (abs‘𝐴))) = ((𝐴 + -𝐴) + ((abs‘𝐴) + (abs‘𝐴)))) | 
| 33 | 4 | negidd 8327 | 
. . . . . 6
⊢ (𝐴 ∈ ℝ → (𝐴 + -𝐴) = 0) | 
| 34 | 33 | oveq1d 5937 | 
. . . . 5
⊢ (𝐴 ∈ ℝ → ((𝐴 + -𝐴) + ((abs‘𝐴) + (abs‘𝐴))) = (0 + ((abs‘𝐴) + (abs‘𝐴)))) | 
| 35 | 25, 25 | addcld 8046 | 
. . . . . 6
⊢ (𝐴 ∈ ℝ →
((abs‘𝐴) +
(abs‘𝐴)) ∈
ℂ) | 
| 36 | 35 | addlidd 8176 | 
. . . . 5
⊢ (𝐴 ∈ ℝ → (0 +
((abs‘𝐴) +
(abs‘𝐴))) =
((abs‘𝐴) +
(abs‘𝐴))) | 
| 37 | 32, 34, 36 | 3eqtrd 2233 | 
. . . 4
⊢ (𝐴 ∈ ℝ → ((𝐴 + (abs‘𝐴)) + (-𝐴 + (abs‘𝐴))) = ((abs‘𝐴) + (abs‘𝐴))) | 
| 38 | 37 | oveq1d 5937 | 
. . 3
⊢ (𝐴 ∈ ℝ → (((𝐴 + (abs‘𝐴)) + (-𝐴 + (abs‘𝐴))) / 2) = (((abs‘𝐴) + (abs‘𝐴)) / 2)) | 
| 39 | 23, 31, 38 | 3eqtr2d 2235 | 
. 2
⊢ (𝐴 ∈ ℝ →
(sup({𝐴, 0}, ℝ, <
) + sup({-𝐴, 0}, ℝ,
< )) = (((abs‘𝐴) +
(abs‘𝐴)) /
2)) | 
| 40 | 25 | 2timesd 9234 | 
. . 3
⊢ (𝐴 ∈ ℝ → (2
· (abs‘𝐴)) =
((abs‘𝐴) +
(abs‘𝐴))) | 
| 41 | 40 | oveq1d 5937 | 
. 2
⊢ (𝐴 ∈ ℝ → ((2
· (abs‘𝐴)) /
2) = (((abs‘𝐴) +
(abs‘𝐴)) /
2)) | 
| 42 | 25, 28, 30 | divcanap3d 8822 | 
. 2
⊢ (𝐴 ∈ ℝ → ((2
· (abs‘𝐴)) /
2) = (abs‘𝐴)) | 
| 43 | 39, 41, 42 | 3eqtr2d 2235 | 
1
⊢ (𝐴 ∈ ℝ →
(sup({𝐴, 0}, ℝ, <
) + sup({-𝐴, 0}, ℝ,
< )) = (abs‘𝐴)) |