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Mirrors > Home > ILE Home > Th. List > op1stbg | GIF version |
Description: Extract the first member of an ordered pair. Theorem 73 of [Suppes] p. 42. (Contributed by Jim Kingdon, 17-Dec-2018.) |
Ref | Expression |
---|---|
op1stbg | ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∩ ∩ 〈𝐴, 𝐵〉 = 𝐴) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dfopg 3739 | . . . . 5 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → 〈𝐴, 𝐵〉 = {{𝐴}, {𝐴, 𝐵}}) | |
2 | 1 | inteqd 3812 | . . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∩ 〈𝐴, 𝐵〉 = ∩ {{𝐴}, {𝐴, 𝐵}}) |
3 | snexg 4145 | . . . . . 6 ⊢ (𝐴 ∈ 𝑉 → {𝐴} ∈ V) | |
4 | prexg 4171 | . . . . . 6 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → {𝐴, 𝐵} ∈ V) | |
5 | intprg 3840 | . . . . . 6 ⊢ (({𝐴} ∈ V ∧ {𝐴, 𝐵} ∈ V) → ∩ {{𝐴}, {𝐴, 𝐵}} = ({𝐴} ∩ {𝐴, 𝐵})) | |
6 | 3, 4, 5 | syl2an2r 585 | . . . . 5 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∩ {{𝐴}, {𝐴, 𝐵}} = ({𝐴} ∩ {𝐴, 𝐵})) |
7 | snsspr1 3704 | . . . . . 6 ⊢ {𝐴} ⊆ {𝐴, 𝐵} | |
8 | df-ss 3115 | . . . . . 6 ⊢ ({𝐴} ⊆ {𝐴, 𝐵} ↔ ({𝐴} ∩ {𝐴, 𝐵}) = {𝐴}) | |
9 | 7, 8 | mpbi 144 | . . . . 5 ⊢ ({𝐴} ∩ {𝐴, 𝐵}) = {𝐴} |
10 | 6, 9 | eqtrdi 2206 | . . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∩ {{𝐴}, {𝐴, 𝐵}} = {𝐴}) |
11 | 2, 10 | eqtrd 2190 | . . 3 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∩ 〈𝐴, 𝐵〉 = {𝐴}) |
12 | 11 | inteqd 3812 | . 2 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∩ ∩ 〈𝐴, 𝐵〉 = ∩ {𝐴}) |
13 | intsng 3841 | . . 3 ⊢ (𝐴 ∈ 𝑉 → ∩ {𝐴} = 𝐴) | |
14 | 13 | adantr 274 | . 2 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∩ {𝐴} = 𝐴) |
15 | 12, 14 | eqtrd 2190 | 1 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∩ ∩ 〈𝐴, 𝐵〉 = 𝐴) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 = wceq 1335 ∈ wcel 2128 Vcvv 2712 ∩ cin 3101 ⊆ wss 3102 {csn 3560 {cpr 3561 〈cop 3563 ∩ cint 3807 |
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 4082 ax-pow 4135 ax-pr 4169 |
This theorem depends on definitions: df-bi 116 df-3an 965 df-tru 1338 df-nf 1441 df-sb 1743 df-clab 2144 df-cleq 2150 df-clel 2153 df-nfc 2288 df-ral 2440 df-v 2714 df-un 3106 df-in 3108 df-ss 3115 df-pw 3545 df-sn 3566 df-pr 3567 df-op 3569 df-int 3808 |
This theorem is referenced by: elxp5 5074 fundmen 6751 |
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