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Single Idea 13802

[from 'Intermediate Logic' by David Bostock, in 8. Modes of Existence / A. Relations / 4. Formal Relations / a. Types of relation ]

Full Idea

A relation is 'one-many' if for anything on the right there is at most one on the left (∀xyz(Rxz∧Ryz→x=y), and is 'many-one' if for anything on the left there is at most one on the right (∀xyz(Rzx∧Rzy→x=y).

Gist of Idea

Relations can be one-many (at most one on the left) or many-one (at most one on the right)

Source

David Bostock (Intermediate Logic [1997], 8.1)

Book Reference

Bostock,David: 'Intermediate Logic' [OUP 1997], p.328