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Theorem alcomiw 2041
Description: Weak version of alcom 2153. Uses only Tarski's FOL axiom schemes. (Contributed by NM, 10-Apr-2017.) (Proof shortened by Wolf Lammen, 28-Dec-2023.)
Hypothesis
Ref Expression
alcomiw.1 (𝑦 = 𝑧 → (𝜑𝜓))
Assertion
Ref Expression
alcomiw (∀𝑥𝑦𝜑 → ∀𝑦𝑥𝜑)
Distinct variable groups:   𝑦,𝑧   𝑥,𝑦   𝜑,𝑧   𝜓,𝑦
Allowed substitution hints:   𝜑(𝑥,𝑦)   𝜓(𝑥,𝑧)

Proof of Theorem alcomiw
StepHypRef Expression
1 alcomiw.1 . . . . 5 (𝑦 = 𝑧 → (𝜑𝜓))
21cbvalvw 2034 . . . 4 (∀𝑦𝜑 ↔ ∀𝑧𝜓)
32biimpi 217 . . 3 (∀𝑦𝜑 → ∀𝑧𝜓)
43alimi 1803 . 2 (∀𝑥𝑦𝜑 → ∀𝑥𝑧𝜓)
5 ax-5 1902 . 2 (∀𝑥𝑧𝜓 → ∀𝑦𝑥𝑧𝜓)
61biimprd 249 . . . . 5 (𝑦 = 𝑧 → (𝜓𝜑))
76equcoms 2018 . . . 4 (𝑧 = 𝑦 → (𝜓𝜑))
87spimvw 1993 . . 3 (∀𝑧𝜓𝜑)
982alimi 1804 . 2 (∀𝑦𝑥𝑧𝜓 → ∀𝑦𝑥𝜑)
104, 5, 93syl 18 1 (∀𝑥𝑦𝜑 → ∀𝑦𝑥𝜑)
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 207  wal 1526
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1787  ax-4 1801  ax-5 1902  ax-6 1961  ax-7 2006
This theorem depends on definitions:  df-bi 208  df-an 397  df-ex 1772
This theorem is referenced by:  hbalw  2047  ax11w  2125  bj-ssblem2  33885
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