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| Description: A conjunction with a stable consequent is stable. See stabnot 834 for negation , bj-stan 15393 for conjunction , and bj-stal 15395 for universal quantification. (Contributed by BJ, 24-Nov-2023.) | 
| Ref | Expression | 
|---|---|
| bj-stim | ⊢ (STAB 𝜓 → STAB (𝜑 → 𝜓)) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | bj-nnim 15381 | . . 3 ⊢ (¬ ¬ (𝜑 → 𝜓) → (𝜑 → ¬ ¬ 𝜓)) | |
| 2 | imim2 55 | . . 3 ⊢ ((¬ ¬ 𝜓 → 𝜓) → ((𝜑 → ¬ ¬ 𝜓) → (𝜑 → 𝜓))) | |
| 3 | 1, 2 | syl5 32 | . 2 ⊢ ((¬ ¬ 𝜓 → 𝜓) → (¬ ¬ (𝜑 → 𝜓) → (𝜑 → 𝜓))) | 
| 4 | df-stab 832 | . 2 ⊢ (STAB 𝜓 ↔ (¬ ¬ 𝜓 → 𝜓)) | |
| 5 | df-stab 832 | . 2 ⊢ (STAB (𝜑 → 𝜓) ↔ (¬ ¬ (𝜑 → 𝜓) → (𝜑 → 𝜓))) | |
| 6 | 3, 4, 5 | 3imtr4i 201 | 1 ⊢ (STAB 𝜓 → STAB (𝜑 → 𝜓)) | 
| Colors of variables: wff set class | 
| Syntax hints: ¬ wn 3 → wi 4 STAB wstab 831 | 
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-in1 615 ax-in2 616 | 
| This theorem depends on definitions: df-bi 117 df-stab 832 | 
| This theorem is referenced by: (None) | 
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