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Theorem alseubii 50667
Description: Congruence: equivalents may be substituted inside an "all some one". This is the "all some one" counterpart of alsbii 50635. (Contributed by David A. Wheeler, 21-Jul-2026.)
Hypotheses
Ref Expression
alseubii.1 (𝜑𝜒)
alseubii.2 (𝜓𝜃)
Assertion
Ref Expression
alseubii (∀∃!𝑥(𝜑𝜓) ↔ ∀∃!𝑥(𝜒𝜃))

Proof of Theorem alseubii
StepHypRef Expression
1 alseubii.1 . . . . 5 (𝜑𝜒)
2 alseubii.2 . . . . 5 (𝜓𝜃)
31, 2imbi12i 353 . . . 4 ((𝜑𝜓) ↔ (𝜒𝜃))
43albii 1852 . . 3 (∀𝑥(𝜑𝜓) ↔ ∀𝑥(𝜒𝜃))
51eubii 2615 . . 3 (∃!𝑥𝜑 ↔ ∃!𝑥𝜒)
64, 5anbi12i 640 . 2 ((∀𝑥(𝜑𝜓) ∧ ∃!𝑥𝜑) ↔ (∀𝑥(𝜒𝜃) ∧ ∃!𝑥𝜒))
7 df-alseu 50656 . 2 (∀∃!𝑥(𝜑𝜓) ↔ (∀𝑥(𝜑𝜓) ∧ ∃!𝑥𝜑))
8 df-alseu 50656 . 2 (∀∃!𝑥(𝜒𝜃) ↔ (∀𝑥(𝜒𝜃) ∧ ∃!𝑥𝜒))
96, 7, 83bitr4i 306 1 (∀∃!𝑥(𝜑𝜓) ↔ ∀∃!𝑥(𝜒𝜃))
Colors of variables:    wff setvar class
This proof depends on syntax axioms:  wi 4  wb 209  wa 401  wal 1568  ∃!weu 2598  ∀∃!walseu 50654
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041
This proof depends on definitions:  df-bi 210  df-an 402  df-ex 1813  df-mo 2569  df-eu 2599  df-alseu 50656
This theorem is used by: (None)
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