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Theorem sbccom2fi 34418
Description: Commutative law for double class substitution, with nonfree variable condition and in inference form. (Contributed by Giovanni Mascellani, 1-Jun-2019.)
Hypotheses
Ref Expression
sbccom2fi.1 𝐴 ∈ V
sbccom2fi.2 𝑦𝐴
sbccom2fi.3 𝐴 / 𝑥𝐵 = 𝐶
sbccom2fi.4 ([𝐴 / 𝑥]𝜑𝜓)
Assertion
Ref Expression
sbccom2fi ([𝐴 / 𝑥][𝐵 / 𝑦]𝜑[𝐶 / 𝑦]𝜓)
Distinct variable group:   𝑥,𝑦
Allowed substitution hints:   𝜑(𝑥,𝑦)   𝜓(𝑥,𝑦)   𝐴(𝑥,𝑦)   𝐵(𝑥,𝑦)   𝐶(𝑥,𝑦)

Proof of Theorem sbccom2fi
StepHypRef Expression
1 sbccom2fi.1 . . 3 𝐴 ∈ V
2 sbccom2fi.2 . . 3 𝑦𝐴
31, 2sbccom2f 34417 . 2 ([𝐴 / 𝑥][𝐵 / 𝑦]𝜑[𝐴 / 𝑥𝐵 / 𝑦][𝐴 / 𝑥]𝜑)
4 sbccom2fi.3 . . 3 𝐴 / 𝑥𝐵 = 𝐶
5 dfsbcq 3635 . . 3 (𝐴 / 𝑥𝐵 = 𝐶 → ([𝐴 / 𝑥𝐵 / 𝑦][𝐴 / 𝑥]𝜑[𝐶 / 𝑦][𝐴 / 𝑥]𝜑))
64, 5ax-mp 5 . 2 ([𝐴 / 𝑥𝐵 / 𝑦][𝐴 / 𝑥]𝜑[𝐶 / 𝑦][𝐴 / 𝑥]𝜑)
7 sbccom2fi.4 . . 3 ([𝐴 / 𝑥]𝜑𝜓)
87sbcbii 3689 . 2 ([𝐶 / 𝑦][𝐴 / 𝑥]𝜑[𝐶 / 𝑦]𝜓)
93, 6, 83bitri 289 1 ([𝐴 / 𝑥][𝐵 / 𝑦]𝜑[𝐶 / 𝑦]𝜓)
Colors of variables: wff setvar class
Syntax hints:  wb 198   = wceq 1653  wcel 2157  wnfc 2928  Vcvv 3385  [wsbc 3633  csb 3728
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1891  ax-4 1905  ax-5 2006  ax-6 2072  ax-7 2107  ax-9 2166  ax-10 2185  ax-11 2200  ax-12 2213  ax-13 2377  ax-ext 2777
This theorem depends on definitions:  df-bi 199  df-an 386  df-or 875  df-3an 1110  df-tru 1657  df-ex 1876  df-nf 1880  df-sb 2065  df-clab 2786  df-cleq 2792  df-clel 2795  df-nfc 2930  df-v 3387  df-sbc 3634  df-csb 3729
This theorem is referenced by:  csbcom2fi  34420
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