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Mirrors > Home > ILE Home > Th. List > fvsng | GIF version |
Description: The value of a singleton of an ordered pair is the second member. (Contributed by NM, 26-Oct-2012.) |
Ref | Expression |
---|---|
fvsng | ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ({〈𝐴, 𝐵〉}‘𝐴) = 𝐵) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | opeq1 3742 | . . . . 5 ⊢ (𝑎 = 𝐴 → 〈𝑎, 𝑏〉 = 〈𝐴, 𝑏〉) | |
2 | 1 | sneqd 3573 | . . . 4 ⊢ (𝑎 = 𝐴 → {〈𝑎, 𝑏〉} = {〈𝐴, 𝑏〉}) |
3 | id 19 | . . . 4 ⊢ (𝑎 = 𝐴 → 𝑎 = 𝐴) | |
4 | 2, 3 | fveq12d 5476 | . . 3 ⊢ (𝑎 = 𝐴 → ({〈𝑎, 𝑏〉}‘𝑎) = ({〈𝐴, 𝑏〉}‘𝐴)) |
5 | 4 | eqeq1d 2166 | . 2 ⊢ (𝑎 = 𝐴 → (({〈𝑎, 𝑏〉}‘𝑎) = 𝑏 ↔ ({〈𝐴, 𝑏〉}‘𝐴) = 𝑏)) |
6 | opeq2 3743 | . . . . 5 ⊢ (𝑏 = 𝐵 → 〈𝐴, 𝑏〉 = 〈𝐴, 𝐵〉) | |
7 | 6 | sneqd 3573 | . . . 4 ⊢ (𝑏 = 𝐵 → {〈𝐴, 𝑏〉} = {〈𝐴, 𝐵〉}) |
8 | 7 | fveq1d 5471 | . . 3 ⊢ (𝑏 = 𝐵 → ({〈𝐴, 𝑏〉}‘𝐴) = ({〈𝐴, 𝐵〉}‘𝐴)) |
9 | id 19 | . . 3 ⊢ (𝑏 = 𝐵 → 𝑏 = 𝐵) | |
10 | 8, 9 | eqeq12d 2172 | . 2 ⊢ (𝑏 = 𝐵 → (({〈𝐴, 𝑏〉}‘𝐴) = 𝑏 ↔ ({〈𝐴, 𝐵〉}‘𝐴) = 𝐵)) |
11 | vex 2715 | . . 3 ⊢ 𝑎 ∈ V | |
12 | vex 2715 | . . 3 ⊢ 𝑏 ∈ V | |
13 | 11, 12 | fvsn 5663 | . 2 ⊢ ({〈𝑎, 𝑏〉}‘𝑎) = 𝑏 |
14 | 5, 10, 13 | vtocl2g 2776 | 1 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ({〈𝐴, 𝐵〉}‘𝐴) = 𝐵) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 = wceq 1335 ∈ wcel 2128 {csn 3560 〈cop 3563 ‘cfv 5171 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-io 699 ax-5 1427 ax-7 1428 ax-gen 1429 ax-ie1 1473 ax-ie2 1474 ax-8 1484 ax-10 1485 ax-11 1486 ax-i12 1487 ax-bndl 1489 ax-4 1490 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 ax-14 2131 ax-ext 2139 ax-sep 4083 ax-pow 4136 ax-pr 4170 |
This theorem depends on definitions: df-bi 116 df-3an 965 df-tru 1338 df-nf 1441 df-sb 1743 df-eu 2009 df-mo 2010 df-clab 2144 df-cleq 2150 df-clel 2153 df-nfc 2288 df-ral 2440 df-rex 2441 df-v 2714 df-sbc 2938 df-un 3106 df-in 3108 df-ss 3115 df-pw 3545 df-sn 3566 df-pr 3567 df-op 3569 df-uni 3774 df-br 3967 df-opab 4027 df-id 4254 df-xp 4593 df-rel 4594 df-cnv 4595 df-co 4596 df-dm 4597 df-iota 5136 df-fun 5173 df-fv 5179 |
This theorem is referenced by: fsnunfv 5669 fvpr1g 5674 fvpr2g 5675 tfr0dm 6270 fseq1p1m1 9997 1fv 10042 sumsnf 11310 prodsnf 11493 setsslid 12282 |
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