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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 3711 | . . . . 5 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → 〈𝐴, 𝐵〉 = {{𝐴}, {𝐴, 𝐵}}) | |
2 | 1 | inteqd 3784 | . . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∩ 〈𝐴, 𝐵〉 = ∩ {{𝐴}, {𝐴, 𝐵}}) |
3 | snexg 4116 | . . . . . 6 ⊢ (𝐴 ∈ 𝑉 → {𝐴} ∈ V) | |
4 | prexg 4141 | . . . . . 6 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → {𝐴, 𝐵} ∈ V) | |
5 | intprg 3812 | . . . . . 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 3676 | . . . . . 6 ⊢ {𝐴} ⊆ {𝐴, 𝐵} | |
8 | df-ss 3089 | . . . . . 6 ⊢ ({𝐴} ⊆ {𝐴, 𝐵} ↔ ({𝐴} ∩ {𝐴, 𝐵}) = {𝐴}) | |
9 | 7, 8 | mpbi 144 | . . . . 5 ⊢ ({𝐴} ∩ {𝐴, 𝐵}) = {𝐴} |
10 | 6, 9 | eqtrdi 2189 | . . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∩ {{𝐴}, {𝐴, 𝐵}} = {𝐴}) |
11 | 2, 10 | eqtrd 2173 | . . 3 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∩ 〈𝐴, 𝐵〉 = {𝐴}) |
12 | 11 | inteqd 3784 | . 2 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∩ ∩ 〈𝐴, 𝐵〉 = ∩ {𝐴}) |
13 | intsng 3813 | . . 3 ⊢ (𝐴 ∈ 𝑉 → ∩ {𝐴} = 𝐴) | |
14 | 13 | adantr 274 | . 2 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∩ {𝐴} = 𝐴) |
15 | 12, 14 | eqtrd 2173 | 1 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ∩ ∩ 〈𝐴, 𝐵〉 = 𝐴) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 = wceq 1332 ∈ wcel 1481 Vcvv 2689 ∩ cin 3075 ⊆ wss 3076 {csn 3532 {cpr 3533 〈cop 3535 ∩ cint 3779 |
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 1424 ax-7 1425 ax-gen 1426 ax-ie1 1470 ax-ie2 1471 ax-8 1483 ax-10 1484 ax-11 1485 ax-i12 1486 ax-bndl 1487 ax-4 1488 ax-14 1493 ax-17 1507 ax-i9 1511 ax-ial 1515 ax-i5r 1516 ax-ext 2122 ax-sep 4054 ax-pow 4106 ax-pr 4139 |
This theorem depends on definitions: df-bi 116 df-3an 965 df-tru 1335 df-nf 1438 df-sb 1737 df-clab 2127 df-cleq 2133 df-clel 2136 df-nfc 2271 df-ral 2422 df-v 2691 df-un 3080 df-in 3082 df-ss 3089 df-pw 3517 df-sn 3538 df-pr 3539 df-op 3541 df-int 3780 |
This theorem is referenced by: elxp5 5035 fundmen 6708 |
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