Step |
Hyp |
Ref |
Expression |
1 |
|
df-he |
⊢ ( 𝑅 hereditary 𝐴 ↔ ( 𝑅 “ 𝐴 ) ⊆ 𝐴 ) |
2 |
|
19.21v |
⊢ ( ∀ 𝑦 ( 𝑥 ∈ 𝐴 → ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ↔ ( 𝑥 ∈ 𝐴 → ∀ 𝑦 ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ) |
3 |
2
|
bicomi |
⊢ ( ( 𝑥 ∈ 𝐴 → ∀ 𝑦 ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ↔ ∀ 𝑦 ( 𝑥 ∈ 𝐴 → ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ) |
4 |
3
|
albii |
⊢ ( ∀ 𝑥 ( 𝑥 ∈ 𝐴 → ∀ 𝑦 ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ↔ ∀ 𝑥 ∀ 𝑦 ( 𝑥 ∈ 𝐴 → ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ) |
5 |
|
alcom |
⊢ ( ∀ 𝑥 ∀ 𝑦 ( 𝑥 ∈ 𝐴 → ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ↔ ∀ 𝑦 ∀ 𝑥 ( 𝑥 ∈ 𝐴 → ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ) |
6 |
|
impexp |
⊢ ( ( ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) → 𝑦 ∈ 𝐴 ) ↔ ( 𝑥 ∈ 𝐴 → ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ) |
7 |
6
|
bicomi |
⊢ ( ( 𝑥 ∈ 𝐴 → ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ↔ ( ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) → 𝑦 ∈ 𝐴 ) ) |
8 |
7
|
albii |
⊢ ( ∀ 𝑥 ( 𝑥 ∈ 𝐴 → ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ↔ ∀ 𝑥 ( ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) → 𝑦 ∈ 𝐴 ) ) |
9 |
|
19.23v |
⊢ ( ∀ 𝑥 ( ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) → 𝑦 ∈ 𝐴 ) ↔ ( ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) → 𝑦 ∈ 𝐴 ) ) |
10 |
8 9
|
bitri |
⊢ ( ∀ 𝑥 ( 𝑥 ∈ 𝐴 → ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ↔ ( ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) → 𝑦 ∈ 𝐴 ) ) |
11 |
10
|
albii |
⊢ ( ∀ 𝑦 ∀ 𝑥 ( 𝑥 ∈ 𝐴 → ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ↔ ∀ 𝑦 ( ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) → 𝑦 ∈ 𝐴 ) ) |
12 |
4 5 11
|
3bitri |
⊢ ( ∀ 𝑥 ( 𝑥 ∈ 𝐴 → ∀ 𝑦 ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ↔ ∀ 𝑦 ( ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) → 𝑦 ∈ 𝐴 ) ) |
13 |
|
dfss2 |
⊢ ( { 𝑧 ∣ ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 〈 𝑥 , 𝑧 〉 ∈ 𝑅 ) } ⊆ 𝐴 ↔ ∀ 𝑦 ( 𝑦 ∈ { 𝑧 ∣ ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 〈 𝑥 , 𝑧 〉 ∈ 𝑅 ) } → 𝑦 ∈ 𝐴 ) ) |
14 |
|
vex |
⊢ 𝑦 ∈ V |
15 |
|
opeq2 |
⊢ ( 𝑧 = 𝑦 → 〈 𝑥 , 𝑧 〉 = 〈 𝑥 , 𝑦 〉 ) |
16 |
15
|
eleq1d |
⊢ ( 𝑧 = 𝑦 → ( 〈 𝑥 , 𝑧 〉 ∈ 𝑅 ↔ 〈 𝑥 , 𝑦 〉 ∈ 𝑅 ) ) |
17 |
|
df-br |
⊢ ( 𝑥 𝑅 𝑦 ↔ 〈 𝑥 , 𝑦 〉 ∈ 𝑅 ) |
18 |
16 17
|
bitr4di |
⊢ ( 𝑧 = 𝑦 → ( 〈 𝑥 , 𝑧 〉 ∈ 𝑅 ↔ 𝑥 𝑅 𝑦 ) ) |
19 |
18
|
anbi2d |
⊢ ( 𝑧 = 𝑦 → ( ( 𝑥 ∈ 𝐴 ∧ 〈 𝑥 , 𝑧 〉 ∈ 𝑅 ) ↔ ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) ) ) |
20 |
19
|
exbidv |
⊢ ( 𝑧 = 𝑦 → ( ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 〈 𝑥 , 𝑧 〉 ∈ 𝑅 ) ↔ ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) ) ) |
21 |
14 20
|
elab |
⊢ ( 𝑦 ∈ { 𝑧 ∣ ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 〈 𝑥 , 𝑧 〉 ∈ 𝑅 ) } ↔ ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) ) |
22 |
21
|
imbi1i |
⊢ ( ( 𝑦 ∈ { 𝑧 ∣ ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 〈 𝑥 , 𝑧 〉 ∈ 𝑅 ) } → 𝑦 ∈ 𝐴 ) ↔ ( ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) → 𝑦 ∈ 𝐴 ) ) |
23 |
22
|
albii |
⊢ ( ∀ 𝑦 ( 𝑦 ∈ { 𝑧 ∣ ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 〈 𝑥 , 𝑧 〉 ∈ 𝑅 ) } → 𝑦 ∈ 𝐴 ) ↔ ∀ 𝑦 ( ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) → 𝑦 ∈ 𝐴 ) ) |
24 |
13 23
|
bitr2i |
⊢ ( ∀ 𝑦 ( ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) → 𝑦 ∈ 𝐴 ) ↔ { 𝑧 ∣ ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 〈 𝑥 , 𝑧 〉 ∈ 𝑅 ) } ⊆ 𝐴 ) |
25 |
|
dfima3 |
⊢ ( 𝑅 “ 𝐴 ) = { 𝑧 ∣ ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 〈 𝑥 , 𝑧 〉 ∈ 𝑅 ) } |
26 |
25
|
eqcomi |
⊢ { 𝑧 ∣ ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 〈 𝑥 , 𝑧 〉 ∈ 𝑅 ) } = ( 𝑅 “ 𝐴 ) |
27 |
26
|
sseq1i |
⊢ ( { 𝑧 ∣ ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 〈 𝑥 , 𝑧 〉 ∈ 𝑅 ) } ⊆ 𝐴 ↔ ( 𝑅 “ 𝐴 ) ⊆ 𝐴 ) |
28 |
24 27
|
bitri |
⊢ ( ∀ 𝑦 ( ∃ 𝑥 ( 𝑥 ∈ 𝐴 ∧ 𝑥 𝑅 𝑦 ) → 𝑦 ∈ 𝐴 ) ↔ ( 𝑅 “ 𝐴 ) ⊆ 𝐴 ) |
29 |
12 28
|
bitr2i |
⊢ ( ( 𝑅 “ 𝐴 ) ⊆ 𝐴 ↔ ∀ 𝑥 ( 𝑥 ∈ 𝐴 → ∀ 𝑦 ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ) |
30 |
1 29
|
bitri |
⊢ ( 𝑅 hereditary 𝐴 ↔ ∀ 𝑥 ( 𝑥 ∈ 𝐴 → ∀ 𝑦 ( 𝑥 𝑅 𝑦 → 𝑦 ∈ 𝐴 ) ) ) |