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Mirrors > Home > NFE Home > Th. List > euabex | GIF version |
Description: If there is a unique object satisfying a property φ, then the set of all elements that satisfy φ exists. (Contributed by SF, 16-Jan-2015.) |
Ref | Expression |
---|---|
euabex | ⊢ (∃!xφ → {x ∣ φ} ∈ V) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dfeu2 4333 | . 2 ⊢ (∃!xφ ↔ {x ∣ φ} ∈ 1c) | |
2 | elex 2867 | . 2 ⊢ ({x ∣ φ} ∈ 1c → {x ∣ φ} ∈ V) | |
3 | 1, 2 | sylbi 187 | 1 ⊢ (∃!xφ → {x ∣ φ} ∈ V) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∈ wcel 1710 ∃!weu 2204 {cab 2339 Vcvv 2859 1cc1c 4134 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-3 7 ax-mp 8 ax-gen 1546 ax-5 1557 ax-17 1616 ax-9 1654 ax-8 1675 ax-6 1729 ax-7 1734 ax-11 1746 ax-12 1925 ax-ext 2334 ax-nin 4078 ax-sn 4087 |
This theorem depends on definitions: df-bi 177 df-or 359 df-an 360 df-nan 1288 df-tru 1319 df-ex 1542 df-nf 1545 df-sb 1649 df-eu 2208 df-clab 2340 df-cleq 2346 df-clel 2349 df-nfc 2478 df-ne 2518 df-v 2861 df-nin 3211 df-compl 3212 df-in 3213 df-un 3214 df-dif 3215 df-ss 3259 df-nul 3551 df-sn 3741 df-1c 4136 |
This theorem is referenced by: dfiota4 4372 |
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