direct derivability造句

例句与造句

1. Direct derivability is a relation between a sentence and a finite, possibly empty set of sentences.
2. A " formal system " can be formally defined as an ordered triple \ mathcal { I }, \ mathcal { D } d >, where \ mathcal { D } d is the relation of direct derivability.
3. It's difficult to find direct derivability in a sentence. 用direct derivability造句挺难的