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Theorem bj-ssbbi 32261
 Description: Biconditional property for substitution, closed form. Specialization of biconditional. Uses only ax-1--5. Compare spsbbi 2401. (Contributed by BJ, 22-Dec-2020.)
Assertion
Ref Expression
bj-ssbbi (∀𝑥(𝜑𝜓) → ([𝑡/𝑥]b𝜑 ↔ [𝑡/𝑥]b𝜓))

Proof of Theorem bj-ssbbi
StepHypRef Expression
1 biimp 205 . . . 4 ((𝜑𝜓) → (𝜑𝜓))
21alimi 1736 . . 3 (∀𝑥(𝜑𝜓) → ∀𝑥(𝜑𝜓))
3 bj-ssbim 32260 . . 3 (∀𝑥(𝜑𝜓) → ([𝑡/𝑥]b𝜑 → [𝑡/𝑥]b𝜓))
42, 3syl 17 . 2 (∀𝑥(𝜑𝜓) → ([𝑡/𝑥]b𝜑 → [𝑡/𝑥]b𝜓))
5 biimpr 210 . . . 4 ((𝜑𝜓) → (𝜓𝜑))
65alimi 1736 . . 3 (∀𝑥(𝜑𝜓) → ∀𝑥(𝜓𝜑))
7 bj-ssbim 32260 . . 3 (∀𝑥(𝜓𝜑) → ([𝑡/𝑥]b𝜓 → [𝑡/𝑥]b𝜑))
86, 7syl 17 . 2 (∀𝑥(𝜑𝜓) → ([𝑡/𝑥]b𝜓 → [𝑡/𝑥]b𝜑))
94, 8impbid 202 1 (∀𝑥(𝜑𝜓) → ([𝑡/𝑥]b𝜑 ↔ [𝑡/𝑥]b𝜓))
 Colors of variables: wff setvar class Syntax hints:   → wi 4   ↔ wb 196  ∀wal 1478  [wssb 32258 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1719  ax-4 1734  ax-5 1836 This theorem depends on definitions:  df-bi 197  df-ssb 32259 This theorem is referenced by:  bj-ssbbii  32263
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