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Mirrors > Home > ILE Home > Th. List > onsucelsucexmidlem1 | GIF version |
Description: Lemma for onsucelsucexmid 4501. (Contributed by Jim Kingdon, 2-Aug-2019.) |
Ref | Expression |
---|---|
onsucelsucexmidlem1 | ⊢ ∅ ∈ {𝑥 ∈ {∅, {∅}} ∣ (𝑥 = ∅ ∨ 𝜑)} |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 0ex 4103 | . . 3 ⊢ ∅ ∈ V | |
2 | 1 | prid1 3676 | . 2 ⊢ ∅ ∈ {∅, {∅}} |
3 | eqid 2164 | . . 3 ⊢ ∅ = ∅ | |
4 | 3 | orci 721 | . 2 ⊢ (∅ = ∅ ∨ 𝜑) |
5 | eqeq1 2171 | . . . 4 ⊢ (𝑥 = ∅ → (𝑥 = ∅ ↔ ∅ = ∅)) | |
6 | 5 | orbi1d 781 | . . 3 ⊢ (𝑥 = ∅ → ((𝑥 = ∅ ∨ 𝜑) ↔ (∅ = ∅ ∨ 𝜑))) |
7 | 6 | elrab 2877 | . 2 ⊢ (∅ ∈ {𝑥 ∈ {∅, {∅}} ∣ (𝑥 = ∅ ∨ 𝜑)} ↔ (∅ ∈ {∅, {∅}} ∧ (∅ = ∅ ∨ 𝜑))) |
8 | 2, 4, 7 | mpbir2an 931 | 1 ⊢ ∅ ∈ {𝑥 ∈ {∅, {∅}} ∣ (𝑥 = ∅ ∨ 𝜑)} |
Colors of variables: wff set class |
Syntax hints: ∨ wo 698 = wceq 1342 ∈ wcel 2135 {crab 2446 ∅c0 3404 {csn 3570 {cpr 3571 |
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 1434 ax-7 1435 ax-gen 1436 ax-ie1 1480 ax-ie2 1481 ax-8 1491 ax-10 1492 ax-11 1493 ax-i12 1494 ax-bndl 1496 ax-4 1497 ax-17 1513 ax-i9 1517 ax-ial 1521 ax-i5r 1522 ax-ext 2146 ax-nul 4102 |
This theorem depends on definitions: df-bi 116 df-tru 1345 df-nf 1448 df-sb 1750 df-clab 2151 df-cleq 2157 df-clel 2160 df-nfc 2295 df-rab 2451 df-v 2723 df-dif 3113 df-un 3115 df-nul 3405 df-sn 3576 df-pr 3577 |
This theorem is referenced by: onsucelsucexmidlem 4500 onsucelsucexmid 4501 acexmidlem2 5833 |
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