例句與造句

1. Here is an attempt to explain the motivation for the definition of \ psi in intuitive terms : since the usual operations of addition, multiplication and exponentiation are not sufficient to designate ordinals very far, we attempt to systematically create new names for ordinals by taking the first one which does not have a name yet, and whenever we run out of names, rather than invent them in an " ad hoc " fashion or using diagonal schemes, we seek them in the ordinals far beyond the ones we are constructing ( beyond \ Omega, that is ); so we give names to uncountable ordinals and, since in the end the list of names is necessarily countable, \ psi will  collapse them to countable ordinals.
2. It's difficult to find diagonal scheme in a sentence. 用diagonal scheme造句挺難的