| Mathbox for Richard Penner |
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| Mirrors > Home > MPE Home > Th. List > Mathboxes > axfrege52c | Structured version Visualization version GIF version | ||
| Description: Justification for ax-frege52c 44672. (Contributed by RP, 24-Dec-2019.) |
| Ref | Expression |
|---|---|
| axfrege52c | ⊢ (𝐴 = 𝐵 → ([𝐴 / 𝑥]𝜑 → [𝐵 / 𝑥]𝜑)) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | dfsbcq 3748 | . 2 ⊢ (𝐴 = 𝐵 → ([𝐴 / 𝑥]𝜑 ↔ [𝐵 / 𝑥]𝜑)) | |
| 2 | 1 | biimpd 232 | 1 ⊢ (𝐴 = 𝐵 → ([𝐴 / 𝑥]𝜑 → [𝐵 / 𝑥]𝜑)) |
| Colors of variables: wff setvar class |
| This proof depends on syntax axioms: → wi 4 = wceq 1570 [wsbc 3746 |
| This proof depends on axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1828 ax-4 1842 ax-5 1943 ax-6 2000 ax-7 2041 ax-8 2148 ax-9 2156 ax-ext 2737 |
| This proof depends on definitions: df-bi 210 df-an 402 df-ex 1813 df-cleq 2757 df-clel 2840 df-sbc 3747 |
| This theorem is used by: (None) |
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