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Mirrors > Home > ILE Home > Th. List > pr2nelem | GIF version |
Description: Lemma for pr2ne 7128. (Contributed by FL, 17-Aug-2008.) |
Ref | Expression |
---|---|
pr2nelem | ⊢ ((𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐷 ∧ 𝐴 ≠ 𝐵) → {𝐴, 𝐵} ≈ 2o) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | disjsn2 3623 | . . 3 ⊢ (𝐴 ≠ 𝐵 → ({𝐴} ∩ {𝐵}) = ∅) | |
2 | ensn1g 6743 | . . . . 5 ⊢ (𝐴 ∈ 𝐶 → {𝐴} ≈ 1o) | |
3 | ensn1g 6743 | . . . . 5 ⊢ (𝐵 ∈ 𝐷 → {𝐵} ≈ 1o) | |
4 | pm54.43 7126 | . . . . . . 7 ⊢ (({𝐴} ≈ 1o ∧ {𝐵} ≈ 1o) → (({𝐴} ∩ {𝐵}) = ∅ ↔ ({𝐴} ∪ {𝐵}) ≈ 2o)) | |
5 | df-pr 3567 | . . . . . . . 8 ⊢ {𝐴, 𝐵} = ({𝐴} ∪ {𝐵}) | |
6 | 5 | breq1i 3973 | . . . . . . 7 ⊢ ({𝐴, 𝐵} ≈ 2o ↔ ({𝐴} ∪ {𝐵}) ≈ 2o) |
7 | 4, 6 | bitr4di 197 | . . . . . 6 ⊢ (({𝐴} ≈ 1o ∧ {𝐵} ≈ 1o) → (({𝐴} ∩ {𝐵}) = ∅ ↔ {𝐴, 𝐵} ≈ 2o)) |
8 | 7 | biimpd 143 | . . . . 5 ⊢ (({𝐴} ≈ 1o ∧ {𝐵} ≈ 1o) → (({𝐴} ∩ {𝐵}) = ∅ → {𝐴, 𝐵} ≈ 2o)) |
9 | 2, 3, 8 | syl2an 287 | . . . 4 ⊢ ((𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐷) → (({𝐴} ∩ {𝐵}) = ∅ → {𝐴, 𝐵} ≈ 2o)) |
10 | 9 | ex 114 | . . 3 ⊢ (𝐴 ∈ 𝐶 → (𝐵 ∈ 𝐷 → (({𝐴} ∩ {𝐵}) = ∅ → {𝐴, 𝐵} ≈ 2o))) |
11 | 1, 10 | syl7 69 | . 2 ⊢ (𝐴 ∈ 𝐶 → (𝐵 ∈ 𝐷 → (𝐴 ≠ 𝐵 → {𝐴, 𝐵} ≈ 2o))) |
12 | 11 | 3imp 1176 | 1 ⊢ ((𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐷 ∧ 𝐴 ≠ 𝐵) → {𝐴, 𝐵} ≈ 2o) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 ∧ w3a 963 = wceq 1335 ∈ wcel 2128 ≠ wne 2327 ∪ cun 3100 ∩ cin 3101 ∅c0 3394 {csn 3560 {cpr 3561 class class class wbr 3966 1oc1o 6357 2oc2o 6358 ≈ cen 6684 |
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-in1 604 ax-in2 605 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-13 2130 ax-14 2131 ax-ext 2139 ax-sep 4083 ax-nul 4091 ax-pow 4136 ax-pr 4170 ax-un 4394 ax-setind 4497 ax-iinf 4548 |
This theorem depends on definitions: df-bi 116 df-dc 821 df-3or 964 df-3an 965 df-tru 1338 df-fal 1341 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-ne 2328 df-ral 2440 df-rex 2441 df-reu 2442 df-rab 2444 df-v 2714 df-sbc 2938 df-dif 3104 df-un 3106 df-in 3108 df-ss 3115 df-nul 3395 df-pw 3545 df-sn 3566 df-pr 3567 df-op 3569 df-uni 3774 df-int 3809 df-br 3967 df-opab 4027 df-tr 4064 df-id 4254 df-iord 4327 df-on 4329 df-suc 4332 df-iom 4551 df-xp 4593 df-rel 4594 df-cnv 4595 df-co 4596 df-dm 4597 df-rn 4598 df-res 4599 df-ima 4600 df-iota 5136 df-fun 5173 df-fn 5174 df-f 5175 df-f1 5176 df-fo 5177 df-f1o 5178 df-fv 5179 df-1o 6364 df-2o 6365 df-er 6481 df-en 6687 |
This theorem is referenced by: pr2ne 7128 |
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