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Theorem reu6 3377
Description: A way to express restricted uniqueness. (Contributed by NM, 20-Oct-2006.)
Assertion
Ref Expression
reu6 (∃!𝑥𝐴 𝜑 ↔ ∃𝑦𝐴𝑥𝐴 (𝜑𝑥 = 𝑦))
Distinct variable groups:   𝑥,𝑦,𝐴   𝜑,𝑦
Allowed substitution hint:   𝜑(𝑥)

Proof of Theorem reu6
StepHypRef Expression
1 df-reu 2914 . 2 (∃!𝑥𝐴 𝜑 ↔ ∃!𝑥(𝑥𝐴𝜑))
2 19.28v 1906 . . . . 5 (∀𝑥(𝑦𝐴 ∧ (𝑥𝐴 → (𝜑𝑥 = 𝑦))) ↔ (𝑦𝐴 ∧ ∀𝑥(𝑥𝐴 → (𝜑𝑥 = 𝑦))))
3 eleq1 2686 . . . . . . . . . . . 12 (𝑥 = 𝑦 → (𝑥𝐴𝑦𝐴))
4 sbequ12 2108 . . . . . . . . . . . 12 (𝑥 = 𝑦 → (𝜑 ↔ [𝑦 / 𝑥]𝜑))
53, 4anbi12d 746 . . . . . . . . . . 11 (𝑥 = 𝑦 → ((𝑥𝐴𝜑) ↔ (𝑦𝐴 ∧ [𝑦 / 𝑥]𝜑)))
6 equequ1 1949 . . . . . . . . . . 11 (𝑥 = 𝑦 → (𝑥 = 𝑦𝑦 = 𝑦))
75, 6bibi12d 335 . . . . . . . . . 10 (𝑥 = 𝑦 → (((𝑥𝐴𝜑) ↔ 𝑥 = 𝑦) ↔ ((𝑦𝐴 ∧ [𝑦 / 𝑥]𝜑) ↔ 𝑦 = 𝑦)))
8 equid 1936 . . . . . . . . . . . 12 𝑦 = 𝑦
98tbt 359 . . . . . . . . . . 11 ((𝑦𝐴 ∧ [𝑦 / 𝑥]𝜑) ↔ ((𝑦𝐴 ∧ [𝑦 / 𝑥]𝜑) ↔ 𝑦 = 𝑦))
10 simpl 473 . . . . . . . . . . 11 ((𝑦𝐴 ∧ [𝑦 / 𝑥]𝜑) → 𝑦𝐴)
119, 10sylbir 225 . . . . . . . . . 10 (((𝑦𝐴 ∧ [𝑦 / 𝑥]𝜑) ↔ 𝑦 = 𝑦) → 𝑦𝐴)
127, 11syl6bi 243 . . . . . . . . 9 (𝑥 = 𝑦 → (((𝑥𝐴𝜑) ↔ 𝑥 = 𝑦) → 𝑦𝐴))
1312spimv 2256 . . . . . . . 8 (∀𝑥((𝑥𝐴𝜑) ↔ 𝑥 = 𝑦) → 𝑦𝐴)
14 ibar 525 . . . . . . . . . . 11 (𝑥𝐴 → (𝜑 ↔ (𝑥𝐴𝜑)))
1514bibi1d 333 . . . . . . . . . 10 (𝑥𝐴 → ((𝜑𝑥 = 𝑦) ↔ ((𝑥𝐴𝜑) ↔ 𝑥 = 𝑦)))
1615biimprcd 240 . . . . . . . . 9 (((𝑥𝐴𝜑) ↔ 𝑥 = 𝑦) → (𝑥𝐴 → (𝜑𝑥 = 𝑦)))
1716sps 2053 . . . . . . . 8 (∀𝑥((𝑥𝐴𝜑) ↔ 𝑥 = 𝑦) → (𝑥𝐴 → (𝜑𝑥 = 𝑦)))
1813, 17jca 554 . . . . . . 7 (∀𝑥((𝑥𝐴𝜑) ↔ 𝑥 = 𝑦) → (𝑦𝐴 ∧ (𝑥𝐴 → (𝜑𝑥 = 𝑦))))
1918axc4i 2127 . . . . . 6 (∀𝑥((𝑥𝐴𝜑) ↔ 𝑥 = 𝑦) → ∀𝑥(𝑦𝐴 ∧ (𝑥𝐴 → (𝜑𝑥 = 𝑦))))
20 biimp 205 . . . . . . . . . . 11 ((𝜑𝑥 = 𝑦) → (𝜑𝑥 = 𝑦))
2120imim2i 16 . . . . . . . . . 10 ((𝑥𝐴 → (𝜑𝑥 = 𝑦)) → (𝑥𝐴 → (𝜑𝑥 = 𝑦)))
2221impd 447 . . . . . . . . 9 ((𝑥𝐴 → (𝜑𝑥 = 𝑦)) → ((𝑥𝐴𝜑) → 𝑥 = 𝑦))
2322adantl 482 . . . . . . . 8 ((𝑦𝐴 ∧ (𝑥𝐴 → (𝜑𝑥 = 𝑦))) → ((𝑥𝐴𝜑) → 𝑥 = 𝑦))
24 eleq1a 2693 . . . . . . . . . . . 12 (𝑦𝐴 → (𝑥 = 𝑦𝑥𝐴))
2524adantr 481 . . . . . . . . . . 11 ((𝑦𝐴 ∧ (𝑥𝐴 → (𝜑𝑥 = 𝑦))) → (𝑥 = 𝑦𝑥𝐴))
2625imp 445 . . . . . . . . . 10 (((𝑦𝐴 ∧ (𝑥𝐴 → (𝜑𝑥 = 𝑦))) ∧ 𝑥 = 𝑦) → 𝑥𝐴)
27 biimpr 210 . . . . . . . . . . . . . 14 ((𝜑𝑥 = 𝑦) → (𝑥 = 𝑦𝜑))
2827imim2i 16 . . . . . . . . . . . . 13 ((𝑥𝐴 → (𝜑𝑥 = 𝑦)) → (𝑥𝐴 → (𝑥 = 𝑦𝜑)))
2928com23 86 . . . . . . . . . . . 12 ((𝑥𝐴 → (𝜑𝑥 = 𝑦)) → (𝑥 = 𝑦 → (𝑥𝐴𝜑)))
3029imp 445 . . . . . . . . . . 11 (((𝑥𝐴 → (𝜑𝑥 = 𝑦)) ∧ 𝑥 = 𝑦) → (𝑥𝐴𝜑))
3130adantll 749 . . . . . . . . . 10 (((𝑦𝐴 ∧ (𝑥𝐴 → (𝜑𝑥 = 𝑦))) ∧ 𝑥 = 𝑦) → (𝑥𝐴𝜑))
3226, 31jcai 558 . . . . . . . . 9 (((𝑦𝐴 ∧ (𝑥𝐴 → (𝜑𝑥 = 𝑦))) ∧ 𝑥 = 𝑦) → (𝑥𝐴𝜑))
3332ex 450 . . . . . . . 8 ((𝑦𝐴 ∧ (𝑥𝐴 → (𝜑𝑥 = 𝑦))) → (𝑥 = 𝑦 → (𝑥𝐴𝜑)))
3423, 33impbid 202 . . . . . . 7 ((𝑦𝐴 ∧ (𝑥𝐴 → (𝜑𝑥 = 𝑦))) → ((𝑥𝐴𝜑) ↔ 𝑥 = 𝑦))
3534alimi 1736 . . . . . 6 (∀𝑥(𝑦𝐴 ∧ (𝑥𝐴 → (𝜑𝑥 = 𝑦))) → ∀𝑥((𝑥𝐴𝜑) ↔ 𝑥 = 𝑦))
3619, 35impbii 199 . . . . 5 (∀𝑥((𝑥𝐴𝜑) ↔ 𝑥 = 𝑦) ↔ ∀𝑥(𝑦𝐴 ∧ (𝑥𝐴 → (𝜑𝑥 = 𝑦))))
37 df-ral 2912 . . . . . 6 (∀𝑥𝐴 (𝜑𝑥 = 𝑦) ↔ ∀𝑥(𝑥𝐴 → (𝜑𝑥 = 𝑦)))
3837anbi2i 729 . . . . 5 ((𝑦𝐴 ∧ ∀𝑥𝐴 (𝜑𝑥 = 𝑦)) ↔ (𝑦𝐴 ∧ ∀𝑥(𝑥𝐴 → (𝜑𝑥 = 𝑦))))
392, 36, 383bitr4i 292 . . . 4 (∀𝑥((𝑥𝐴𝜑) ↔ 𝑥 = 𝑦) ↔ (𝑦𝐴 ∧ ∀𝑥𝐴 (𝜑𝑥 = 𝑦)))
4039exbii 1771 . . 3 (∃𝑦𝑥((𝑥𝐴𝜑) ↔ 𝑥 = 𝑦) ↔ ∃𝑦(𝑦𝐴 ∧ ∀𝑥𝐴 (𝜑𝑥 = 𝑦)))
41 df-eu 2473 . . 3 (∃!𝑥(𝑥𝐴𝜑) ↔ ∃𝑦𝑥((𝑥𝐴𝜑) ↔ 𝑥 = 𝑦))
42 df-rex 2913 . . 3 (∃𝑦𝐴𝑥𝐴 (𝜑𝑥 = 𝑦) ↔ ∃𝑦(𝑦𝐴 ∧ ∀𝑥𝐴 (𝜑𝑥 = 𝑦)))
4340, 41, 423bitr4i 292 . 2 (∃!𝑥(𝑥𝐴𝜑) ↔ ∃𝑦𝐴𝑥𝐴 (𝜑𝑥 = 𝑦))
441, 43bitri 264 1 (∃!𝑥𝐴 𝜑 ↔ ∃𝑦𝐴𝑥𝐴 (𝜑𝑥 = 𝑦))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 196  wa 384  wal 1478  wex 1701  [wsb 1877  wcel 1987  ∃!weu 2469  wral 2907  wrex 2908  ∃!wreu 2909
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1719  ax-4 1734  ax-5 1836  ax-6 1885  ax-7 1932  ax-9 1996  ax-10 2016  ax-12 2044  ax-13 2245  ax-ext 2601
This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-ex 1702  df-nf 1707  df-sb 1878  df-eu 2473  df-cleq 2614  df-clel 2617  df-ral 2912  df-rex 2913  df-reu 2914
This theorem is referenced by:  reu3  3378  reu6i  3379  reu8  3384  xpf1o  8066  ufileu  21633  isppw2  24741  cusgrfilem2  26239  fgreu  29314  fcnvgreu  29315  fourierdlem50  39680
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