Читать книгу Selected Mathematical Works: Symbolic Logic + The Game of Logic + Feeding the Mind: by Charles Lutwidge Dodgson, alias Lewis Carroll - Lewis Carroll - Страница 45

Henceforwards, in stating such Propositions as “Some x-Things exist” or “No x-Things are y-Things”, I shall omit the word “Things”, which the Reader can supply for himself, and shall write them as “Some x exist” or “No x are y”.

[Note that the word “Things” is here used with a special meaning, as explained at p. 23.]

A Proposition, containing only one of the Letters used as Symbols for Attributes, is said to be ‘Uniliteral’.

[For example, “Some x exist”, “No y′ exist”, &c.]

A Proposition, containing two Letters, is said to be ‘Biliteral’.

[For example, “Some xy′ exist”, “No x′ are y”, &c.]

A Proposition is said to be ‘in terms of’ the Letters it contains, whether with or without accents.

[Thus, “Some xy′ exist”, “No x′ are y”, &c., are said to be in terms of x and y.]