Proof of Theorem mapsn
Step | Hyp | Ref
| Expression |
1 | | map0.1 |
. . 3
⊢ A ∈
V |
2 | | snex 4112 |
. . 3
⊢ {B} ∈
V |
3 | 1, 2 | mapval 6012 |
. 2
⊢ (A ↑m {B}) = {f ∣ f:{B}–→A} |
4 | | ffn 5224 |
. . . . . . . 8
⊢ (f:{B}–→A
→ f Fn {B}) |
5 | | map0.2 |
. . . . . . . . 9
⊢ B ∈
V |
6 | 5 | snid 3761 |
. . . . . . . 8
⊢ B ∈ {B} |
7 | | fneu 5188 |
. . . . . . . 8
⊢ ((f Fn {B} ∧ B ∈ {B}) →
∃!y
Bfy) |
8 | 4, 6, 7 | sylancl 643 |
. . . . . . 7
⊢ (f:{B}–→A
→ ∃!y Bfy) |
9 | | euabsn 3793 |
. . . . . . . 8
⊢ (∃!y Bfy ↔ ∃y{y ∣ Bfy} = {y}) |
10 | | imadmrn 5009 |
. . . . . . . . . . . 12
⊢ (f “ dom f)
= ran f |
11 | | fdm 5227 |
. . . . . . . . . . . . 13
⊢ (f:{B}–→A
→ dom f = {B}) |
12 | 11 | imaeq2d 4943 |
. . . . . . . . . . . 12
⊢ (f:{B}–→A
→ (f “ dom f) = (f “
{B})) |
13 | 10, 12 | syl5eqr 2399 |
. . . . . . . . . . 11
⊢ (f:{B}–→A
→ ran f = (f “ {B})) |
14 | | imasn 5019 |
. . . . . . . . . . 11
⊢ (f “ {B}) =
{y ∣
Bfy} |
15 | 13, 14 | syl6req 2402 |
. . . . . . . . . 10
⊢ (f:{B}–→A
→ {y ∣ Bfy} = ran
f) |
16 | 15 | eqeq1d 2361 |
. . . . . . . . 9
⊢ (f:{B}–→A
→ ({y ∣ Bfy} = {y} ↔ ran f
= {y})) |
17 | 16 | exbidv 1626 |
. . . . . . . 8
⊢ (f:{B}–→A
→ (∃y{y ∣ Bfy} = {y} ↔ ∃yran f = {y})) |
18 | 9, 17 | syl5bb 248 |
. . . . . . 7
⊢ (f:{B}–→A
→ (∃!y Bfy ↔ ∃yran f = {y})) |
19 | 8, 18 | mpbid 201 |
. . . . . 6
⊢ (f:{B}–→A
→ ∃yran f =
{y}) |
20 | | frn 5229 |
. . . . . . . . 9
⊢ (f:{B}–→A
→ ran f ⊆ A) |
21 | | sseq1 3293 |
. . . . . . . . . 10
⊢ (ran f = {y} →
(ran f ⊆
A ↔ {y} ⊆ A)) |
22 | | vex 2863 |
. . . . . . . . . . 11
⊢ y ∈
V |
23 | 22 | snss 3839 |
. . . . . . . . . 10
⊢ (y ∈ A ↔ {y}
⊆ A) |
24 | 21, 23 | syl6bbr 254 |
. . . . . . . . 9
⊢ (ran f = {y} →
(ran f ⊆
A ↔ y ∈ A)) |
25 | 20, 24 | syl5ibcom 211 |
. . . . . . . 8
⊢ (f:{B}–→A
→ (ran f = {y} → y
∈ A)) |
26 | | dffn4 5276 |
. . . . . . . . . . . 12
⊢ (f Fn {B} ↔
f:{B}–onto→ran f) |
27 | 4, 26 | sylib 188 |
. . . . . . . . . . 11
⊢ (f:{B}–→A
→ f:{B}–onto→ran f) |
28 | | fof 5270 |
. . . . . . . . . . 11
⊢ (f:{B}–onto→ran f
→ f:{B}–→ran f) |
29 | 27, 28 | syl 15 |
. . . . . . . . . 10
⊢ (f:{B}–→A
→ f:{B}–→ran f) |
30 | | feq3 5213 |
. . . . . . . . . 10
⊢ (ran f = {y} →
(f:{B}–→ran f ↔ f:{B}–→{y})) |
31 | 29, 30 | syl5ibcom 211 |
. . . . . . . . 9
⊢ (f:{B}–→A
→ (ran f = {y} → f:{B}–→{y})) |
32 | 5, 22 | fsn 5433 |
. . . . . . . . 9
⊢ (f:{B}–→{y} ↔ f =
{〈B,
y〉}) |
33 | 31, 32 | syl6ib 217 |
. . . . . . . 8
⊢ (f:{B}–→A
→ (ran f = {y} → f =
{〈B,
y〉})) |
34 | 25, 33 | jcad 519 |
. . . . . . 7
⊢ (f:{B}–→A
→ (ran f = {y} → (y
∈ A ∧ f = {〈B, y〉}))) |
35 | 34 | eximdv 1622 |
. . . . . 6
⊢ (f:{B}–→A
→ (∃yran f =
{y} → ∃y(y ∈ A ∧ f = {〈B, y〉}))) |
36 | 19, 35 | mpd 14 |
. . . . 5
⊢ (f:{B}–→A
→ ∃y(y ∈ A ∧ f = {〈B, y〉})) |
37 | | df-rex 2621 |
. . . . 5
⊢ (∃y ∈ A f = {〈B, y〉} ↔ ∃y(y ∈ A ∧ f = {〈B, y〉})) |
38 | 36, 37 | sylibr 203 |
. . . 4
⊢ (f:{B}–→A
→ ∃y ∈ A f = {〈B, y〉}) |
39 | 5, 22 | f1osn 5323 |
. . . . . . . . 9
⊢ {〈B, y〉}:{B}–1-1-onto→{y} |
40 | | f1of 5288 |
. . . . . . . . 9
⊢ ({〈B, y〉}:{B}–1-1-onto→{y} →
{〈B,
y〉}:{B}–→{y}) |
41 | 39, 40 | ax-mp 5 |
. . . . . . . 8
⊢ {〈B, y〉}:{B}–→{y} |
42 | | feq1 5211 |
. . . . . . . 8
⊢ (f = {〈B, y〉} → (f:{B}–→{y} ↔ {〈B, y〉}:{B}–→{y})) |
43 | 41, 42 | mpbiri 224 |
. . . . . . 7
⊢ (f = {〈B, y〉} → f:{B}–→{y}) |
44 | | snssi 3853 |
. . . . . . 7
⊢ (y ∈ A → {y}
⊆ A) |
45 | | fss 5231 |
. . . . . . 7
⊢ ((f:{B}–→{y} ∧ {y} ⊆ A) → f:{B}–→A) |
46 | 43, 44, 45 | syl2an 463 |
. . . . . 6
⊢ ((f = {〈B, y〉} ∧ y ∈ A) → f:{B}–→A) |
47 | 46 | expcom 424 |
. . . . 5
⊢ (y ∈ A → (f =
{〈B,
y〉}
→ f:{B}–→A)) |
48 | 47 | rexlimiv 2733 |
. . . 4
⊢ (∃y ∈ A f = {〈B, y〉} → f:{B}–→A) |
49 | 38, 48 | impbii 180 |
. . 3
⊢ (f:{B}–→A
↔ ∃y ∈ A f = {〈B, y〉}) |
50 | 49 | abbii 2466 |
. 2
⊢ {f ∣ f:{B}–→A} = {f ∣ ∃y ∈ A f = {〈B, y〉}} |
51 | 3, 50 | eqtri 2373 |
1
⊢ (A ↑m {B}) = {f ∣ ∃y ∈ A f = {〈B, y〉}} |