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NotDiFalse

⊢ ¬false NotDiFalse

Proof:

1
⊢ true ⊃true
StateImpBi
2
⊢ true
Prop
3
⊢ true
1, 2,MP
4
⊢ ¬¬true
3, def. of 
5
⊢ ¬true ≡false
Prop
6
⊢ ¬true ≡false
5,DiEqvDi
7
⊢ ¬false
4, 6,Prop

qed

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2023-09-12
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