Step |
Hyp |
Ref |
Expression |
1 |
|
isbasisrelowl.1 |
⊢ 𝐼 = ( [,) “ ( ℝ × ℝ ) ) |
2 |
|
simplr1 |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → 𝑐 ∈ ℝ ) |
3 |
|
simplr2 |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → 𝑑 ∈ ℝ ) |
4 |
|
nfv |
⊢ Ⅎ 𝑧 𝑎 ∈ ℝ |
5 |
|
nfv |
⊢ Ⅎ 𝑧 𝑏 ∈ ℝ |
6 |
|
nfrab1 |
⊢ Ⅎ 𝑧 { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } |
7 |
6
|
nfeq2 |
⊢ Ⅎ 𝑧 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } |
8 |
4 5 7
|
nf3an |
⊢ Ⅎ 𝑧 ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) |
9 |
|
nfv |
⊢ Ⅎ 𝑧 𝑐 ∈ ℝ |
10 |
|
nfv |
⊢ Ⅎ 𝑧 𝑑 ∈ ℝ |
11 |
|
nfrab1 |
⊢ Ⅎ 𝑧 { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } |
12 |
11
|
nfeq2 |
⊢ Ⅎ 𝑧 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } |
13 |
9 10 12
|
nf3an |
⊢ Ⅎ 𝑧 ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) |
14 |
8 13
|
nfan |
⊢ Ⅎ 𝑧 ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) |
15 |
|
nfv |
⊢ Ⅎ 𝑧 ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) |
16 |
14 15
|
nfan |
⊢ Ⅎ 𝑧 ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) |
17 |
|
nfcv |
⊢ Ⅎ 𝑧 ( 𝑥 ∩ 𝑦 ) |
18 |
|
simp3 |
⊢ ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) → 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) |
19 |
|
simp3 |
⊢ ( ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) → 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) |
20 |
|
elin |
⊢ ( 𝑧 ∈ ( 𝑥 ∩ 𝑦 ) ↔ ( 𝑧 ∈ 𝑥 ∧ 𝑧 ∈ 𝑦 ) ) |
21 |
|
eleq2 |
⊢ ( 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } → ( 𝑧 ∈ 𝑥 ↔ 𝑧 ∈ { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ) |
22 |
|
rabid |
⊢ ( 𝑧 ∈ { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ↔ ( 𝑧 ∈ ℝ ∧ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) |
23 |
21 22
|
bitrdi |
⊢ ( 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } → ( 𝑧 ∈ 𝑥 ↔ ( 𝑧 ∈ ℝ ∧ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) ) |
24 |
23
|
anbi1d |
⊢ ( 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } → ( ( 𝑧 ∈ 𝑥 ∧ 𝑧 ∈ 𝑦 ) ↔ ( ( 𝑧 ∈ ℝ ∧ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ∧ 𝑧 ∈ 𝑦 ) ) ) |
25 |
20 24
|
syl5bb |
⊢ ( 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } → ( 𝑧 ∈ ( 𝑥 ∩ 𝑦 ) ↔ ( ( 𝑧 ∈ ℝ ∧ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ∧ 𝑧 ∈ 𝑦 ) ) ) |
26 |
|
eleq2 |
⊢ ( 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } → ( 𝑧 ∈ 𝑦 ↔ 𝑧 ∈ { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) |
27 |
|
rabid |
⊢ ( 𝑧 ∈ { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ↔ ( 𝑧 ∈ ℝ ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) |
28 |
26 27
|
bitrdi |
⊢ ( 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } → ( 𝑧 ∈ 𝑦 ↔ ( 𝑧 ∈ ℝ ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) ) |
29 |
28
|
anbi2d |
⊢ ( 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } → ( ( ( 𝑧 ∈ ℝ ∧ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ∧ 𝑧 ∈ 𝑦 ) ↔ ( ( 𝑧 ∈ ℝ ∧ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ∧ ( 𝑧 ∈ ℝ ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) ) ) |
30 |
25 29
|
sylan9bb |
⊢ ( ( 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) → ( 𝑧 ∈ ( 𝑥 ∩ 𝑦 ) ↔ ( ( 𝑧 ∈ ℝ ∧ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ∧ ( 𝑧 ∈ ℝ ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) ) ) |
31 |
|
an4 |
⊢ ( ( ( 𝑧 ∈ ℝ ∧ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ∧ ( 𝑧 ∈ ℝ ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) ↔ ( ( 𝑧 ∈ ℝ ∧ 𝑧 ∈ ℝ ) ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) ) |
32 |
|
anidm |
⊢ ( ( 𝑧 ∈ ℝ ∧ 𝑧 ∈ ℝ ) ↔ 𝑧 ∈ ℝ ) |
33 |
32
|
anbi1i |
⊢ ( ( ( 𝑧 ∈ ℝ ∧ 𝑧 ∈ ℝ ) ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) ↔ ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) ) |
34 |
31 33
|
bitri |
⊢ ( ( ( 𝑧 ∈ ℝ ∧ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ∧ ( 𝑧 ∈ ℝ ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) ↔ ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) ) |
35 |
|
an4 |
⊢ ( ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ↔ ( ( 𝑎 ≤ 𝑧 ∧ 𝑐 ≤ 𝑧 ) ∧ ( 𝑧 < 𝑑 ∧ 𝑧 < 𝑏 ) ) ) |
36 |
|
an42 |
⊢ ( ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ↔ ( ( 𝑎 ≤ 𝑧 ∧ 𝑐 ≤ 𝑧 ) ∧ ( 𝑧 < 𝑑 ∧ 𝑧 < 𝑏 ) ) ) |
37 |
36
|
bicomi |
⊢ ( ( ( 𝑎 ≤ 𝑧 ∧ 𝑐 ≤ 𝑧 ) ∧ ( 𝑧 < 𝑑 ∧ 𝑧 < 𝑏 ) ) ↔ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) |
38 |
35 37
|
bitri |
⊢ ( ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ↔ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) |
39 |
38
|
bicomi |
⊢ ( ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ↔ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) |
40 |
39
|
anbi2i |
⊢ ( ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) ↔ ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) ) |
41 |
34 40
|
bitri |
⊢ ( ( ( 𝑧 ∈ ℝ ∧ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ∧ ( 𝑧 ∈ ℝ ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) ↔ ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) ) |
42 |
30 41
|
bitrdi |
⊢ ( ( 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) → ( 𝑧 ∈ ( 𝑥 ∩ 𝑦 ) ↔ ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) ) ) |
43 |
18 19 42
|
syl2an |
⊢ ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) → ( 𝑧 ∈ ( 𝑥 ∩ 𝑦 ) ↔ ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) ) ) |
44 |
43
|
adantr |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → ( 𝑧 ∈ ( 𝑥 ∩ 𝑦 ) ↔ ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) ) ) |
45 |
|
simpl |
⊢ ( ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) → 𝑧 ∈ ℝ ) |
46 |
|
simprrl |
⊢ ( ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) → 𝑐 ≤ 𝑧 ) |
47 |
|
simprlr |
⊢ ( ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) → 𝑧 < 𝑑 ) |
48 |
45 46 47
|
jca32 |
⊢ ( ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) → ( 𝑧 ∈ ℝ ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) |
49 |
44 48
|
syl6bi |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → ( 𝑧 ∈ ( 𝑥 ∩ 𝑦 ) → ( 𝑧 ∈ ℝ ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) ) |
50 |
|
3simpa |
⊢ ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) → ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ) ) |
51 |
|
3simpa |
⊢ ( ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) → ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ) ) |
52 |
50 51
|
anim12i |
⊢ ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) → ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ) ) ) |
53 |
|
letr |
⊢ ( ( 𝑎 ∈ ℝ ∧ 𝑐 ∈ ℝ ∧ 𝑧 ∈ ℝ ) → ( ( 𝑎 ≤ 𝑐 ∧ 𝑐 ≤ 𝑧 ) → 𝑎 ≤ 𝑧 ) ) |
54 |
53
|
3expia |
⊢ ( ( 𝑎 ∈ ℝ ∧ 𝑐 ∈ ℝ ) → ( 𝑧 ∈ ℝ → ( ( 𝑎 ≤ 𝑐 ∧ 𝑐 ≤ 𝑧 ) → 𝑎 ≤ 𝑧 ) ) ) |
55 |
54
|
exp4a |
⊢ ( ( 𝑎 ∈ ℝ ∧ 𝑐 ∈ ℝ ) → ( 𝑧 ∈ ℝ → ( 𝑎 ≤ 𝑐 → ( 𝑐 ≤ 𝑧 → 𝑎 ≤ 𝑧 ) ) ) ) |
56 |
55
|
ad2ant2r |
⊢ ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ) ) → ( 𝑧 ∈ ℝ → ( 𝑎 ≤ 𝑐 → ( 𝑐 ≤ 𝑧 → 𝑎 ≤ 𝑧 ) ) ) ) |
57 |
|
ltletr |
⊢ ( ( 𝑧 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑏 ∈ ℝ ) → ( ( 𝑧 < 𝑑 ∧ 𝑑 ≤ 𝑏 ) → 𝑧 < 𝑏 ) ) |
58 |
57
|
3com13 |
⊢ ( ( 𝑏 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑧 ∈ ℝ ) → ( ( 𝑧 < 𝑑 ∧ 𝑑 ≤ 𝑏 ) → 𝑧 < 𝑏 ) ) |
59 |
58
|
expcomd |
⊢ ( ( 𝑏 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑧 ∈ ℝ ) → ( 𝑑 ≤ 𝑏 → ( 𝑧 < 𝑑 → 𝑧 < 𝑏 ) ) ) |
60 |
59
|
3expia |
⊢ ( ( 𝑏 ∈ ℝ ∧ 𝑑 ∈ ℝ ) → ( 𝑧 ∈ ℝ → ( 𝑑 ≤ 𝑏 → ( 𝑧 < 𝑑 → 𝑧 < 𝑏 ) ) ) ) |
61 |
60
|
ad2ant2l |
⊢ ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ) ) → ( 𝑧 ∈ ℝ → ( 𝑑 ≤ 𝑏 → ( 𝑧 < 𝑑 → 𝑧 < 𝑏 ) ) ) ) |
62 |
56 61
|
jcad |
⊢ ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ) ) → ( 𝑧 ∈ ℝ → ( ( 𝑎 ≤ 𝑐 → ( 𝑐 ≤ 𝑧 → 𝑎 ≤ 𝑧 ) ) ∧ ( 𝑑 ≤ 𝑏 → ( 𝑧 < 𝑑 → 𝑧 < 𝑏 ) ) ) ) ) |
63 |
|
anim12 |
⊢ ( ( ( 𝑎 ≤ 𝑐 → ( 𝑐 ≤ 𝑧 → 𝑎 ≤ 𝑧 ) ) ∧ ( 𝑑 ≤ 𝑏 → ( 𝑧 < 𝑑 → 𝑧 < 𝑏 ) ) ) → ( ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) → ( ( 𝑐 ≤ 𝑧 → 𝑎 ≤ 𝑧 ) ∧ ( 𝑧 < 𝑑 → 𝑧 < 𝑏 ) ) ) ) |
64 |
62 63
|
syl6 |
⊢ ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ) ) → ( 𝑧 ∈ ℝ → ( ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) → ( ( 𝑐 ≤ 𝑧 → 𝑎 ≤ 𝑧 ) ∧ ( 𝑧 < 𝑑 → 𝑧 < 𝑏 ) ) ) ) ) |
65 |
64
|
com23 |
⊢ ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ) ) → ( ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) → ( 𝑧 ∈ ℝ → ( ( 𝑐 ≤ 𝑧 → 𝑎 ≤ 𝑧 ) ∧ ( 𝑧 < 𝑑 → 𝑧 < 𝑏 ) ) ) ) ) |
66 |
|
anim12 |
⊢ ( ( ( 𝑐 ≤ 𝑧 → 𝑎 ≤ 𝑧 ) ∧ ( 𝑧 < 𝑑 → 𝑧 < 𝑏 ) ) → ( ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) → ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) |
67 |
65 66
|
syl8 |
⊢ ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ) ) → ( ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) → ( 𝑧 ∈ ℝ → ( ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) → ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) ) ) |
68 |
67
|
imp31 |
⊢ ( ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) ∧ 𝑧 ∈ ℝ ) → ( ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) → ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) |
69 |
68
|
ancrd |
⊢ ( ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) ∧ 𝑧 ∈ ℝ ) → ( ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) → ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) ) |
70 |
|
an42 |
⊢ ( ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ↔ ( ( 𝑎 ≤ 𝑧 ∧ 𝑐 ≤ 𝑧 ) ∧ ( 𝑧 < 𝑏 ∧ 𝑧 < 𝑑 ) ) ) |
71 |
|
an4 |
⊢ ( ( ( 𝑎 ≤ 𝑧 ∧ 𝑐 ≤ 𝑧 ) ∧ ( 𝑧 < 𝑏 ∧ 𝑧 < 𝑑 ) ) ↔ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) |
72 |
70 71
|
bitri |
⊢ ( ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ↔ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) |
73 |
69 72
|
syl6ibr |
⊢ ( ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) ∧ 𝑧 ∈ ℝ ) → ( ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) → ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) ) |
74 |
|
simpr |
⊢ ( ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) ∧ 𝑧 ∈ ℝ ) → 𝑧 ∈ ℝ ) |
75 |
73 74
|
jctild |
⊢ ( ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) ∧ 𝑧 ∈ ℝ ) → ( ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) → ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) ) ) |
76 |
52 75
|
sylanl1 |
⊢ ( ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) ∧ 𝑧 ∈ ℝ ) → ( ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) → ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) ) ) |
77 |
76
|
imp |
⊢ ( ( ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) ∧ 𝑧 ∈ ℝ ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) → ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) ) |
78 |
77
|
an32s |
⊢ ( ( ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ∧ 𝑧 ∈ ℝ ) → ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) ) |
79 |
44
|
adantr |
⊢ ( ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) → ( 𝑧 ∈ ( 𝑥 ∩ 𝑦 ) ↔ ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) ) ) |
80 |
79
|
adantr |
⊢ ( ( ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ∧ 𝑧 ∈ ℝ ) → ( 𝑧 ∈ ( 𝑥 ∩ 𝑦 ) ↔ ( 𝑧 ∈ ℝ ∧ ( ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) ) ) ) ) |
81 |
78 80
|
mpbird |
⊢ ( ( ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ∧ 𝑧 ∈ ℝ ) → 𝑧 ∈ ( 𝑥 ∩ 𝑦 ) ) |
82 |
81
|
expl |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → ( ( ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ∧ 𝑧 ∈ ℝ ) → 𝑧 ∈ ( 𝑥 ∩ 𝑦 ) ) ) |
83 |
82
|
ancomsd |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → ( ( 𝑧 ∈ ℝ ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) → 𝑧 ∈ ( 𝑥 ∩ 𝑦 ) ) ) |
84 |
49 83
|
impbid |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → ( 𝑧 ∈ ( 𝑥 ∩ 𝑦 ) ↔ ( 𝑧 ∈ ℝ ∧ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) ) ) ) |
85 |
84 27
|
bitr4di |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → ( 𝑧 ∈ ( 𝑥 ∩ 𝑦 ) ↔ 𝑧 ∈ { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) |
86 |
16 17 11 85
|
eqrd |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → ( 𝑥 ∩ 𝑦 ) = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) |
87 |
3 86
|
jca |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → ( 𝑑 ∈ ℝ ∧ ( 𝑥 ∩ 𝑦 ) = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) |
88 |
87
|
19.8ad |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → ∃ 𝑑 ( 𝑑 ∈ ℝ ∧ ( 𝑥 ∩ 𝑦 ) = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) |
89 |
|
df-rex |
⊢ ( ∃ 𝑑 ∈ ℝ ( 𝑥 ∩ 𝑦 ) = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ↔ ∃ 𝑑 ( 𝑑 ∈ ℝ ∧ ( 𝑥 ∩ 𝑦 ) = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) |
90 |
88 89
|
sylibr |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → ∃ 𝑑 ∈ ℝ ( 𝑥 ∩ 𝑦 ) = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) |
91 |
2 90
|
jca |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → ( 𝑐 ∈ ℝ ∧ ∃ 𝑑 ∈ ℝ ( 𝑥 ∩ 𝑦 ) = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) |
92 |
91
|
19.8ad |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → ∃ 𝑐 ( 𝑐 ∈ ℝ ∧ ∃ 𝑑 ∈ ℝ ( 𝑥 ∩ 𝑦 ) = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) |
93 |
|
df-rex |
⊢ ( ∃ 𝑐 ∈ ℝ ∃ 𝑑 ∈ ℝ ( 𝑥 ∩ 𝑦 ) = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ↔ ∃ 𝑐 ( 𝑐 ∈ ℝ ∧ ∃ 𝑑 ∈ ℝ ( 𝑥 ∩ 𝑦 ) = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) |
94 |
92 93
|
sylibr |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → ∃ 𝑐 ∈ ℝ ∃ 𝑑 ∈ ℝ ( 𝑥 ∩ 𝑦 ) = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) |
95 |
1
|
icoreelrnab |
⊢ ( ( 𝑥 ∩ 𝑦 ) ∈ 𝐼 ↔ ∃ 𝑐 ∈ ℝ ∃ 𝑑 ∈ ℝ ( 𝑥 ∩ 𝑦 ) = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) |
96 |
94 95
|
sylibr |
⊢ ( ( ( ( 𝑎 ∈ ℝ ∧ 𝑏 ∈ ℝ ∧ 𝑥 = { 𝑧 ∈ ℝ ∣ ( 𝑎 ≤ 𝑧 ∧ 𝑧 < 𝑏 ) } ) ∧ ( 𝑐 ∈ ℝ ∧ 𝑑 ∈ ℝ ∧ 𝑦 = { 𝑧 ∈ ℝ ∣ ( 𝑐 ≤ 𝑧 ∧ 𝑧 < 𝑑 ) } ) ) ∧ ( 𝑎 ≤ 𝑐 ∧ 𝑑 ≤ 𝑏 ) ) → ( 𝑥 ∩ 𝑦 ) ∈ 𝐼 ) |