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Mirrors > Home > MPE Home > Th. List > Mathboxes > bj-axadj | Structured version Visualization version GIF version |
Description: Two ways of stating the axiom of adjunction (which is the universal closure of either side, see ax-bj-adj 37008). (Contributed by BJ, 12-Jan-2025.) (Proof modification is discouraged.) |
Ref | Expression |
---|---|
bj-axadj | ⊢ ((𝑥 ∪ {𝑦}) ∈ V ↔ ∃𝑧∀𝑡(𝑡 ∈ 𝑧 ↔ (𝑡 ∈ 𝑥 ∨ 𝑡 = 𝑦))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elun 4176 | . . 3 ⊢ (𝑡 ∈ (𝑥 ∪ {𝑦}) ↔ (𝑡 ∈ 𝑥 ∨ 𝑡 ∈ {𝑦})) | |
2 | velsn 4664 | . . . 4 ⊢ (𝑡 ∈ {𝑦} ↔ 𝑡 = 𝑦) | |
3 | 2 | orbi2i 911 | . . 3 ⊢ ((𝑡 ∈ 𝑥 ∨ 𝑡 ∈ {𝑦}) ↔ (𝑡 ∈ 𝑥 ∨ 𝑡 = 𝑦)) |
4 | 1, 3 | bitri 275 | . 2 ⊢ (𝑡 ∈ (𝑥 ∪ {𝑦}) ↔ (𝑡 ∈ 𝑥 ∨ 𝑡 = 𝑦)) |
5 | 4 | bj-clex 36997 | 1 ⊢ ((𝑥 ∪ {𝑦}) ∈ V ↔ ∃𝑧∀𝑡(𝑡 ∈ 𝑧 ↔ (𝑡 ∈ 𝑥 ∨ 𝑡 = 𝑦))) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 206 ∨ wo 846 ∀wal 1535 ∃wex 1777 ∈ wcel 2108 Vcvv 3488 ∪ cun 3974 {csn 4648 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1793 ax-4 1807 ax-5 1909 ax-6 1967 ax-7 2007 ax-8 2110 ax-9 2118 ax-ext 2711 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 847 df-tru 1540 df-ex 1778 df-sb 2065 df-clab 2718 df-cleq 2732 df-clel 2819 df-v 3490 df-un 3981 df-sn 4649 |
This theorem is referenced by: bj-adjg1 37009 |
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