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| Mirrors > Home > MPE Home > Th. List > fsng | Structured version Visualization version GIF version | ||
| Description: A function maps a singleton to a singleton iff it is the singleton of an ordered pair. (Contributed by NM, 26-Oct-2012.) |
| Ref | Expression |
|---|---|
| fsng | ⊢ ((𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐷) → (𝐹:{𝐴}⟶{𝐵} ↔ 𝐹 = {〈𝐴, 𝐵〉})) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | sneq 4636 | . . . 4 ⊢ (𝑎 = 𝐴 → {𝑎} = {𝐴}) | |
| 2 | 1 | feq2d 6722 | . . 3 ⊢ (𝑎 = 𝐴 → (𝐹:{𝑎}⟶{𝑏} ↔ 𝐹:{𝐴}⟶{𝑏})) |
| 3 | opeq1 4873 | . . . . 5 ⊢ (𝑎 = 𝐴 → 〈𝑎, 𝑏〉 = 〈𝐴, 𝑏〉) | |
| 4 | 3 | sneqd 4638 | . . . 4 ⊢ (𝑎 = 𝐴 → {〈𝑎, 𝑏〉} = {〈𝐴, 𝑏〉}) |
| 5 | 4 | eqeq2d 2748 | . . 3 ⊢ (𝑎 = 𝐴 → (𝐹 = {〈𝑎, 𝑏〉} ↔ 𝐹 = {〈𝐴, 𝑏〉})) |
| 6 | 2, 5 | bibi12d 345 | . 2 ⊢ (𝑎 = 𝐴 → ((𝐹:{𝑎}⟶{𝑏} ↔ 𝐹 = {〈𝑎, 𝑏〉}) ↔ (𝐹:{𝐴}⟶{𝑏} ↔ 𝐹 = {〈𝐴, 𝑏〉}))) |
| 7 | sneq 4636 | . . . 4 ⊢ (𝑏 = 𝐵 → {𝑏} = {𝐵}) | |
| 8 | 7 | feq3d 6723 | . . 3 ⊢ (𝑏 = 𝐵 → (𝐹:{𝐴}⟶{𝑏} ↔ 𝐹:{𝐴}⟶{𝐵})) |
| 9 | opeq2 4874 | . . . . 5 ⊢ (𝑏 = 𝐵 → 〈𝐴, 𝑏〉 = 〈𝐴, 𝐵〉) | |
| 10 | 9 | sneqd 4638 | . . . 4 ⊢ (𝑏 = 𝐵 → {〈𝐴, 𝑏〉} = {〈𝐴, 𝐵〉}) |
| 11 | 10 | eqeq2d 2748 | . . 3 ⊢ (𝑏 = 𝐵 → (𝐹 = {〈𝐴, 𝑏〉} ↔ 𝐹 = {〈𝐴, 𝐵〉})) |
| 12 | 8, 11 | bibi12d 345 | . 2 ⊢ (𝑏 = 𝐵 → ((𝐹:{𝐴}⟶{𝑏} ↔ 𝐹 = {〈𝐴, 𝑏〉}) ↔ (𝐹:{𝐴}⟶{𝐵} ↔ 𝐹 = {〈𝐴, 𝐵〉}))) |
| 13 | vex 3484 | . . 3 ⊢ 𝑎 ∈ V | |
| 14 | vex 3484 | . . 3 ⊢ 𝑏 ∈ V | |
| 15 | 13, 14 | fsn 7155 | . 2 ⊢ (𝐹:{𝑎}⟶{𝑏} ↔ 𝐹 = {〈𝑎, 𝑏〉}) |
| 16 | 6, 12, 15 | vtocl2g 3574 | 1 ⊢ ((𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐷) → (𝐹:{𝐴}⟶{𝐵} ↔ 𝐹 = {〈𝐴, 𝐵〉})) |
| Colors of variables: wff setvar class |
| Syntax hints: → wi 4 ↔ wb 206 ∧ wa 395 = wceq 1540 ∈ wcel 2108 {csn 4626 〈cop 4632 ⟶wf 6557 |
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1795 ax-4 1809 ax-5 1910 ax-6 1967 ax-7 2007 ax-8 2110 ax-9 2118 ax-ext 2708 ax-sep 5296 ax-nul 5306 ax-pr 5432 |
| This theorem depends on definitions: df-bi 207 df-an 396 df-or 849 df-3an 1089 df-tru 1543 df-fal 1553 df-ex 1780 df-sb 2065 df-mo 2540 df-eu 2569 df-clab 2715 df-cleq 2729 df-clel 2816 df-ral 3062 df-rex 3071 df-reu 3381 df-rab 3437 df-v 3482 df-dif 3954 df-un 3956 df-ss 3968 df-nul 4334 df-if 4526 df-sn 4627 df-pr 4629 df-op 4633 df-br 5144 df-opab 5206 df-id 5578 df-xp 5691 df-rel 5692 df-cnv 5693 df-co 5694 df-dm 5695 df-rn 5696 df-fun 6563 df-fn 6564 df-f 6565 df-f1 6566 df-fo 6567 df-f1o 6568 |
| This theorem is referenced by: xpsng 7159 ftpg 7176 mapsnd 8926 axdc3lem4 10493 fseq1p1m1 13638 cats1un 14759 intopsn 18667 efmnd1bas 18906 grp1inv 19066 symg1bas 19408 esumsnf 34065 bnj149 34889 rngosn3 37931 sticksstones9 42155 sticksstones11 42157 k0004lem3 44162 ovnovollem1 46671 mapsnop 48260 snlindsntorlem 48387 lmod1zr 48410 |
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