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Theorem ralanid 3112
Description: Cancellation law for restricted universal quantification. (Contributed by Peter Mazsa, 30-Dec-2018.) (Proof shortened by Wolf Lammen, 29-Jun-2023.)
Assertion
Ref Expression
ralanid (∀𝑥𝐴 (𝑥𝐴𝜑) ↔ ∀𝑥𝐴 𝜑)

Proof of Theorem ralanid
StepHypRef Expression
1 ibar 537 . . 3 (𝑥𝐴 → (𝜑 ↔ (𝑥𝐴𝜑)))
21bicomd 226 . 2 (𝑥𝐴 → ((𝑥𝐴𝜑) ↔ 𝜑))
32ralbiia 3108 1 (∀𝑥𝐴 (𝑥𝐴𝜑) ↔ ∀𝑥𝐴 𝜑)
Colors of variables:    wff setvar class
This proof depends on syntax axioms:  wb 209  wa 400  wcel 2142  wral 3078
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1824  ax-4 1838
This proof depends on definitions:  df-bi 210  df-an 401  df-ral 3079
This theorem is used by:  idinxpssinxp2  39001
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