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| Mirrors > Home > ILE Home > Th. List > dcbii | GIF version | ||
| Description: Equivalence property for decidability. Inference form. (Contributed by Jim Kingdon, 28-Mar-2018.) | 
| Ref | Expression | 
|---|---|
| dcbii.1 | ⊢ (𝜑 ↔ 𝜓) | 
| Ref | Expression | 
|---|---|
| dcbii | ⊢ (DECID 𝜑 ↔ DECID 𝜓) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | dcbii.1 | . 2 ⊢ (𝜑 ↔ 𝜓) | |
| 2 | dcbiit 840 | . 2 ⊢ ((𝜑 ↔ 𝜓) → (DECID 𝜑 ↔ DECID 𝜓)) | |
| 3 | 1, 2 | ax-mp 5 | 1 ⊢ (DECID 𝜑 ↔ DECID 𝜓) | 
| Colors of variables: wff set class | 
| Syntax hints: ↔ wb 105 DECID wdc 835 | 
| 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 ax-io 710 | 
| This theorem depends on definitions: df-bi 117 df-dc 836 | 
| This theorem is referenced by: dcbi 938 dcned 2373 dfrex2dc 2488 euxfr2dc 2949 exmidexmid 4229 pw1fin 6971 tpfidceq 6991 dcfi 7047 elnn0dc 9685 elnndc 9686 exfzdc 10316 fprod1p 11764 nnwosdc 12206 prmdc 12298 pclemdc 12457 4sqlemafi 12564 4sqleminfi 12566 4sqexercise1 12567 nninfdclemcl 12665 nninfdclemp1 12667 nninfsellemdc 15654 | 
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