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Theorem eqeqan12dALT 2622
Description: Alternate proof of eqeqan12d 2621. This proof has one more step but one fewer essential step. (Contributed by NM, 9-Aug-1994.) (Proof shortened by Andrew Salmon, 25-May-2011.) (Proof modification is discouraged.) (New usage is discouraged.)
Hypotheses
Ref Expression
eqeqan12d.1 (𝜑𝐴 = 𝐵)
eqeqan12d.2 (𝜓𝐶 = 𝐷)
Assertion
Ref Expression
eqeqan12dALT ((𝜑𝜓) → (𝐴 = 𝐶𝐵 = 𝐷))

Proof of Theorem eqeqan12dALT
StepHypRef Expression
1 eqeqan12d.1 . 2 (𝜑𝐴 = 𝐵)
2 eqeqan12d.2 . 2 (𝜓𝐶 = 𝐷)
3 eqeq12 2618 . 2 ((𝐴 = 𝐵𝐶 = 𝐷) → (𝐴 = 𝐶𝐵 = 𝐷))
41, 2, 3syl2an 492 1 ((𝜑𝜓) → (𝐴 = 𝐶𝐵 = 𝐷))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 194  wa 382   = wceq 1474
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1711  ax-4 1726  ax-ext 2585
This theorem depends on definitions:  df-bi 195  df-an 384  df-cleq 2598
This theorem is referenced by: (None)
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