Proof of Theorem mapsn
| Step | Hyp | Ref
| Expression |
| 1 | | map0.1 |
. . . 4
⊢ 𝐴 ∈ V |
| 2 | | map0.2 |
. . . . 5
⊢ 𝐵 ∈ V |
| 3 | 2 | snex 4219 |
. . . 4
⊢ {𝐵} ∈ V |
| 4 | 1, 3 | elmap 6745 |
. . 3
⊢ (𝑓 ∈ (𝐴 ↑𝑚 {𝐵}) ↔ 𝑓:{𝐵}⟶𝐴) |
| 5 | | ffn 5410 |
. . . . . . . 8
⊢ (𝑓:{𝐵}⟶𝐴 → 𝑓 Fn {𝐵}) |
| 6 | 2 | snid 3654 |
. . . . . . . 8
⊢ 𝐵 ∈ {𝐵} |
| 7 | | fneu 5365 |
. . . . . . . 8
⊢ ((𝑓 Fn {𝐵} ∧ 𝐵 ∈ {𝐵}) → ∃!𝑦 𝐵𝑓𝑦) |
| 8 | 5, 6, 7 | sylancl 413 |
. . . . . . 7
⊢ (𝑓:{𝐵}⟶𝐴 → ∃!𝑦 𝐵𝑓𝑦) |
| 9 | | euabsn 3693 |
. . . . . . . 8
⊢
(∃!𝑦 𝐵𝑓𝑦 ↔ ∃𝑦{𝑦 ∣ 𝐵𝑓𝑦} = {𝑦}) |
| 10 | | imasng 5035 |
. . . . . . . . . . . 12
⊢ (𝐵 ∈ V → (𝑓 “ {𝐵}) = {𝑦 ∣ 𝐵𝑓𝑦}) |
| 11 | 2, 10 | ax-mp 5 |
. . . . . . . . . . 11
⊢ (𝑓 “ {𝐵}) = {𝑦 ∣ 𝐵𝑓𝑦} |
| 12 | | fdm 5416 |
. . . . . . . . . . . . 13
⊢ (𝑓:{𝐵}⟶𝐴 → dom 𝑓 = {𝐵}) |
| 13 | 12 | imaeq2d 5010 |
. . . . . . . . . . . 12
⊢ (𝑓:{𝐵}⟶𝐴 → (𝑓 “ dom 𝑓) = (𝑓 “ {𝐵})) |
| 14 | | imadmrn 5020 |
. . . . . . . . . . . 12
⊢ (𝑓 “ dom 𝑓) = ran 𝑓 |
| 15 | 13, 14 | eqtr3di 2244 |
. . . . . . . . . . 11
⊢ (𝑓:{𝐵}⟶𝐴 → (𝑓 “ {𝐵}) = ran 𝑓) |
| 16 | 11, 15 | eqtr3id 2243 |
. . . . . . . . . 10
⊢ (𝑓:{𝐵}⟶𝐴 → {𝑦 ∣ 𝐵𝑓𝑦} = ran 𝑓) |
| 17 | 16 | eqeq1d 2205 |
. . . . . . . . 9
⊢ (𝑓:{𝐵}⟶𝐴 → ({𝑦 ∣ 𝐵𝑓𝑦} = {𝑦} ↔ ran 𝑓 = {𝑦})) |
| 18 | 17 | exbidv 1839 |
. . . . . . . 8
⊢ (𝑓:{𝐵}⟶𝐴 → (∃𝑦{𝑦 ∣ 𝐵𝑓𝑦} = {𝑦} ↔ ∃𝑦ran 𝑓 = {𝑦})) |
| 19 | 9, 18 | bitrid 192 |
. . . . . . 7
⊢ (𝑓:{𝐵}⟶𝐴 → (∃!𝑦 𝐵𝑓𝑦 ↔ ∃𝑦ran 𝑓 = {𝑦})) |
| 20 | 8, 19 | mpbid 147 |
. . . . . 6
⊢ (𝑓:{𝐵}⟶𝐴 → ∃𝑦ran 𝑓 = {𝑦}) |
| 21 | | vex 2766 |
. . . . . . . . . . 11
⊢ 𝑦 ∈ V |
| 22 | 21 | snid 3654 |
. . . . . . . . . 10
⊢ 𝑦 ∈ {𝑦} |
| 23 | | eleq2 2260 |
. . . . . . . . . 10
⊢ (ran
𝑓 = {𝑦} → (𝑦 ∈ ran 𝑓 ↔ 𝑦 ∈ {𝑦})) |
| 24 | 22, 23 | mpbiri 168 |
. . . . . . . . 9
⊢ (ran
𝑓 = {𝑦} → 𝑦 ∈ ran 𝑓) |
| 25 | | frn 5419 |
. . . . . . . . . 10
⊢ (𝑓:{𝐵}⟶𝐴 → ran 𝑓 ⊆ 𝐴) |
| 26 | 25 | sseld 3183 |
. . . . . . . . 9
⊢ (𝑓:{𝐵}⟶𝐴 → (𝑦 ∈ ran 𝑓 → 𝑦 ∈ 𝐴)) |
| 27 | 24, 26 | syl5 32 |
. . . . . . . 8
⊢ (𝑓:{𝐵}⟶𝐴 → (ran 𝑓 = {𝑦} → 𝑦 ∈ 𝐴)) |
| 28 | | dffn4 5489 |
. . . . . . . . . . . 12
⊢ (𝑓 Fn {𝐵} ↔ 𝑓:{𝐵}–onto→ran 𝑓) |
| 29 | 5, 28 | sylib 122 |
. . . . . . . . . . 11
⊢ (𝑓:{𝐵}⟶𝐴 → 𝑓:{𝐵}–onto→ran 𝑓) |
| 30 | | fof 5483 |
. . . . . . . . . . 11
⊢ (𝑓:{𝐵}–onto→ran 𝑓 → 𝑓:{𝐵}⟶ran 𝑓) |
| 31 | 29, 30 | syl 14 |
. . . . . . . . . 10
⊢ (𝑓:{𝐵}⟶𝐴 → 𝑓:{𝐵}⟶ran 𝑓) |
| 32 | | feq3 5395 |
. . . . . . . . . 10
⊢ (ran
𝑓 = {𝑦} → (𝑓:{𝐵}⟶ran 𝑓 ↔ 𝑓:{𝐵}⟶{𝑦})) |
| 33 | 31, 32 | syl5ibcom 155 |
. . . . . . . . 9
⊢ (𝑓:{𝐵}⟶𝐴 → (ran 𝑓 = {𝑦} → 𝑓:{𝐵}⟶{𝑦})) |
| 34 | 2, 21 | fsn 5737 |
. . . . . . . . 9
⊢ (𝑓:{𝐵}⟶{𝑦} ↔ 𝑓 = {〈𝐵, 𝑦〉}) |
| 35 | 33, 34 | imbitrdi 161 |
. . . . . . . 8
⊢ (𝑓:{𝐵}⟶𝐴 → (ran 𝑓 = {𝑦} → 𝑓 = {〈𝐵, 𝑦〉})) |
| 36 | 27, 35 | jcad 307 |
. . . . . . 7
⊢ (𝑓:{𝐵}⟶𝐴 → (ran 𝑓 = {𝑦} → (𝑦 ∈ 𝐴 ∧ 𝑓 = {〈𝐵, 𝑦〉}))) |
| 37 | 36 | eximdv 1894 |
. . . . . 6
⊢ (𝑓:{𝐵}⟶𝐴 → (∃𝑦ran 𝑓 = {𝑦} → ∃𝑦(𝑦 ∈ 𝐴 ∧ 𝑓 = {〈𝐵, 𝑦〉}))) |
| 38 | 20, 37 | mpd 13 |
. . . . 5
⊢ (𝑓:{𝐵}⟶𝐴 → ∃𝑦(𝑦 ∈ 𝐴 ∧ 𝑓 = {〈𝐵, 𝑦〉})) |
| 39 | | df-rex 2481 |
. . . . 5
⊢
(∃𝑦 ∈
𝐴 𝑓 = {〈𝐵, 𝑦〉} ↔ ∃𝑦(𝑦 ∈ 𝐴 ∧ 𝑓 = {〈𝐵, 𝑦〉})) |
| 40 | 38, 39 | sylibr 134 |
. . . 4
⊢ (𝑓:{𝐵}⟶𝐴 → ∃𝑦 ∈ 𝐴 𝑓 = {〈𝐵, 𝑦〉}) |
| 41 | 2, 21 | f1osn 5547 |
. . . . . . . . 9
⊢
{〈𝐵, 𝑦〉}:{𝐵}–1-1-onto→{𝑦} |
| 42 | | f1oeq1 5495 |
. . . . . . . . 9
⊢ (𝑓 = {〈𝐵, 𝑦〉} → (𝑓:{𝐵}–1-1-onto→{𝑦} ↔ {〈𝐵, 𝑦〉}:{𝐵}–1-1-onto→{𝑦})) |
| 43 | 41, 42 | mpbiri 168 |
. . . . . . . 8
⊢ (𝑓 = {〈𝐵, 𝑦〉} → 𝑓:{𝐵}–1-1-onto→{𝑦}) |
| 44 | | f1of 5507 |
. . . . . . . 8
⊢ (𝑓:{𝐵}–1-1-onto→{𝑦} → 𝑓:{𝐵}⟶{𝑦}) |
| 45 | 43, 44 | syl 14 |
. . . . . . 7
⊢ (𝑓 = {〈𝐵, 𝑦〉} → 𝑓:{𝐵}⟶{𝑦}) |
| 46 | | snssi 3767 |
. . . . . . 7
⊢ (𝑦 ∈ 𝐴 → {𝑦} ⊆ 𝐴) |
| 47 | | fss 5422 |
. . . . . . 7
⊢ ((𝑓:{𝐵}⟶{𝑦} ∧ {𝑦} ⊆ 𝐴) → 𝑓:{𝐵}⟶𝐴) |
| 48 | 45, 46, 47 | syl2an 289 |
. . . . . 6
⊢ ((𝑓 = {〈𝐵, 𝑦〉} ∧ 𝑦 ∈ 𝐴) → 𝑓:{𝐵}⟶𝐴) |
| 49 | 48 | expcom 116 |
. . . . 5
⊢ (𝑦 ∈ 𝐴 → (𝑓 = {〈𝐵, 𝑦〉} → 𝑓:{𝐵}⟶𝐴)) |
| 50 | 49 | rexlimiv 2608 |
. . . 4
⊢
(∃𝑦 ∈
𝐴 𝑓 = {〈𝐵, 𝑦〉} → 𝑓:{𝐵}⟶𝐴) |
| 51 | 40, 50 | impbii 126 |
. . 3
⊢ (𝑓:{𝐵}⟶𝐴 ↔ ∃𝑦 ∈ 𝐴 𝑓 = {〈𝐵, 𝑦〉}) |
| 52 | 4, 51 | bitri 184 |
. 2
⊢ (𝑓 ∈ (𝐴 ↑𝑚 {𝐵}) ↔ ∃𝑦 ∈ 𝐴 𝑓 = {〈𝐵, 𝑦〉}) |
| 53 | 52 | abbi2i 2311 |
1
⊢ (𝐴 ↑𝑚
{𝐵}) = {𝑓 ∣ ∃𝑦 ∈ 𝐴 𝑓 = {〈𝐵, 𝑦〉}} |