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Theorem nfeud 2591
Description: Bound-variable hypothesis builder for the unique existential quantifier. Deduction version of nfeu 2593. Usage of this theorem is discouraged because it depends on ax-13 2376. Use the weaker nfeudw 2590 when possible. (Contributed by NM, 15-Feb-2013.) (Revised by Mario Carneiro, 7-Oct-2016.) (New usage is discouraged.)
Hypotheses
Ref Expression
nfeud.1 𝑦𝜑
nfeud.2 (𝜑 → Ⅎ𝑥𝜓)
Assertion
Ref Expression
nfeud (𝜑 → Ⅎ𝑥∃!𝑦𝜓)

Proof of Theorem nfeud
StepHypRef Expression
1 nfeud.1 . 2 𝑦𝜑
2 nfeud.2 . . 3 (𝜑 → Ⅎ𝑥𝜓)
32adantr 480 . 2 ((𝜑 ∧ ¬ ∀𝑥 𝑥 = 𝑦) → Ⅎ𝑥𝜓)
41, 3nfeud2 2589 1 (𝜑 → Ⅎ𝑥∃!𝑦𝜓)
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wal 1537  wnf 1782  ∃!weu 2567
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1794  ax-4 1808  ax-5 1909  ax-6 1966  ax-7 2006  ax-10 2140  ax-11 2156  ax-12 2176  ax-13 2376
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-tru 1542  df-ex 1779  df-nf 1783  df-mo 2539  df-eu 2568
This theorem is referenced by:  nfeu  2593
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