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Theorem bj-sbceqgALT 33219
 Description: Distribute proper substitution through an equality relation. Alternate proof of sbceqg 4127. (Contributed by BJ, 6-Oct-2018.) Proof modification is discouraged to avoid using sbceqg 4127, but "minimize */except sbceqg" is ok. (Proof modification is discouraged.) (New usage is discouraged.)
Assertion
Ref Expression
bj-sbceqgALT (𝐴𝑉 → ([𝐴 / 𝑥]𝐵 = 𝐶𝐴 / 𝑥𝐵 = 𝐴 / 𝑥𝐶))

Proof of Theorem bj-sbceqgALT
Dummy variable 𝑦 is distinct from all other variables.
StepHypRef Expression
1 dfcleq 2754 . . . . . 6 (𝐵 = 𝐶 ↔ ∀𝑦(𝑦𝐵𝑦𝐶))
21sbcth 3591 . . . . 5 (𝐴𝑉[𝐴 / 𝑥](𝐵 = 𝐶 ↔ ∀𝑦(𝑦𝐵𝑦𝐶)))
3 sbcbig 3621 . . . . 5 (𝐴𝑉 → ([𝐴 / 𝑥](𝐵 = 𝐶 ↔ ∀𝑦(𝑦𝐵𝑦𝐶)) ↔ ([𝐴 / 𝑥]𝐵 = 𝐶[𝐴 / 𝑥]𝑦(𝑦𝐵𝑦𝐶))))
42, 3mpbid 222 . . . 4 (𝐴𝑉 → ([𝐴 / 𝑥]𝐵 = 𝐶[𝐴 / 𝑥]𝑦(𝑦𝐵𝑦𝐶)))
5 sbcal 3626 . . . 4 ([𝐴 / 𝑥]𝑦(𝑦𝐵𝑦𝐶) ↔ ∀𝑦[𝐴 / 𝑥](𝑦𝐵𝑦𝐶))
64, 5syl6bb 276 . . 3 (𝐴𝑉 → ([𝐴 / 𝑥]𝐵 = 𝐶 ↔ ∀𝑦[𝐴 / 𝑥](𝑦𝐵𝑦𝐶)))
7 sbcbig 3621 . . . 4 (𝐴𝑉 → ([𝐴 / 𝑥](𝑦𝐵𝑦𝐶) ↔ ([𝐴 / 𝑥]𝑦𝐵[𝐴 / 𝑥]𝑦𝐶)))
87albidv 1998 . . 3 (𝐴𝑉 → (∀𝑦[𝐴 / 𝑥](𝑦𝐵𝑦𝐶) ↔ ∀𝑦([𝐴 / 𝑥]𝑦𝐵[𝐴 / 𝑥]𝑦𝐶)))
9 sbcel2 4132 . . . . . 6 ([𝐴 / 𝑥]𝑦𝐵𝑦𝐴 / 𝑥𝐵)
109a1i 11 . . . . 5 (𝐴𝑉 → ([𝐴 / 𝑥]𝑦𝐵𝑦𝐴 / 𝑥𝐵))
11 sbcel2 4132 . . . . . 6 ([𝐴 / 𝑥]𝑦𝐶𝑦𝐴 / 𝑥𝐶)
1211a1i 11 . . . . 5 (𝐴𝑉 → ([𝐴 / 𝑥]𝑦𝐶𝑦𝐴 / 𝑥𝐶))
1310, 12bibi12d 334 . . . 4 (𝐴𝑉 → (([𝐴 / 𝑥]𝑦𝐵[𝐴 / 𝑥]𝑦𝐶) ↔ (𝑦𝐴 / 𝑥𝐵𝑦𝐴 / 𝑥𝐶)))
1413albidv 1998 . . 3 (𝐴𝑉 → (∀𝑦([𝐴 / 𝑥]𝑦𝐵[𝐴 / 𝑥]𝑦𝐶) ↔ ∀𝑦(𝑦𝐴 / 𝑥𝐵𝑦𝐴 / 𝑥𝐶)))
156, 8, 143bitrd 294 . 2 (𝐴𝑉 → ([𝐴 / 𝑥]𝐵 = 𝐶 ↔ ∀𝑦(𝑦𝐴 / 𝑥𝐵𝑦𝐴 / 𝑥𝐶)))
16 dfcleq 2754 . 2 (𝐴 / 𝑥𝐵 = 𝐴 / 𝑥𝐶 ↔ ∀𝑦(𝑦𝐴 / 𝑥𝐵𝑦𝐴 / 𝑥𝐶))
1715, 16syl6bbr 278 1 (𝐴𝑉 → ([𝐴 / 𝑥]𝐵 = 𝐶𝐴 / 𝑥𝐵 = 𝐴 / 𝑥𝐶))
 Colors of variables: wff setvar class Syntax hints:   → wi 4   ↔ wb 196  ∀wal 1630   = wceq 1632   ∈ wcel 2139  [wsbc 3576  ⦋csb 3674 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1871  ax-4 1886  ax-5 1988  ax-6 2054  ax-7 2090  ax-9 2148  ax-10 2168  ax-11 2183  ax-12 2196  ax-13 2391  ax-ext 2740 This theorem depends on definitions:  df-bi 197  df-or 384  df-an 385  df-tru 1635  df-fal 1638  df-ex 1854  df-nf 1859  df-sb 2047  df-clab 2747  df-cleq 2753  df-clel 2756  df-nfc 2891  df-v 3342  df-sbc 3577  df-csb 3675  df-dif 3718  df-nul 4059 This theorem is referenced by: (None)
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