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Mirrors > Home > MPE Home > Th. List > hbsb | Structured version Visualization version GIF version |
Description: If 𝑧 is not free in 𝜑, it is not free in [𝑦 / 𝑥]𝜑 when 𝑦 and 𝑧 are distinct. (Contributed by NM, 12-Aug-1993.) |
Ref | Expression |
---|---|
hbsb.1 | ⊢ (𝜑 → ∀𝑧𝜑) |
Ref | Expression |
---|---|
hbsb | ⊢ ([𝑦 / 𝑥]𝜑 → ∀𝑧[𝑦 / 𝑥]𝜑) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | hbsb.1 | . . . 4 ⊢ (𝜑 → ∀𝑧𝜑) | |
2 | 1 | nf5i 2024 | . . 3 ⊢ Ⅎ𝑧𝜑 |
3 | 2 | nfsb 2440 | . 2 ⊢ Ⅎ𝑧[𝑦 / 𝑥]𝜑 |
4 | 3 | nf5ri 2065 | 1 ⊢ ([𝑦 / 𝑥]𝜑 → ∀𝑧[𝑦 / 𝑥]𝜑) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∀wal 1481 [wsb 1880 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1722 ax-4 1737 ax-5 1839 ax-6 1888 ax-7 1935 ax-10 2019 ax-11 2034 ax-12 2047 ax-13 2246 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-tru 1486 df-ex 1705 df-nf 1710 df-sb 1881 |
This theorem is referenced by: hbab 2613 hblem 2731 bj-hblem 32849 |
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