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Mirrors > Home > MPE Home > Th. List > Mathboxes > bj-alsb | Structured version Visualization version GIF version |
Description: If a proposition is true for all instances, then it is true for any specific one. See stdpc4 2341. (Contributed by BJ, 22-Dec-2020.) |
Ref | Expression |
---|---|
bj-alsb | ⊢ (∀𝑥𝜑 → [𝑡/𝑥]b𝜑) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ala1 1755 | . . . 4 ⊢ (∀𝑥𝜑 → ∀𝑥(𝑥 = 𝑦 → 𝜑)) | |
2 | 1 | a1d 25 | . . 3 ⊢ (∀𝑥𝜑 → (𝑦 = 𝑡 → ∀𝑥(𝑥 = 𝑦 → 𝜑))) |
3 | 2 | alrimiv 1842 | . 2 ⊢ (∀𝑥𝜑 → ∀𝑦(𝑦 = 𝑡 → ∀𝑥(𝑥 = 𝑦 → 𝜑))) |
4 | df-ssb 31809 | . 2 ⊢ ([𝑡/𝑥]b𝜑 ↔ ∀𝑦(𝑦 = 𝑡 → ∀𝑥(𝑥 = 𝑦 → 𝜑))) | |
5 | 3, 4 | sylibr 223 | 1 ⊢ (∀𝑥𝜑 → [𝑡/𝑥]b𝜑) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∀wal 1473 [wssb 31808 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1713 ax-4 1728 ax-5 1827 |
This theorem depends on definitions: df-bi 196 df-ssb 31809 |
This theorem is referenced by: bj-ssbft 31831 |
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