Definition of a total function

[fresh root]

Does every output have to be unique?

[radiant depot]

no

[gusty salmon]

Every input is unique (*) = function
Every output is unique = injective function

(*) means that a given input cannot give two outputs at the same time.

Strictly speaking, injective function satisfies both conditions (both input and output are unique)

[fresh root]

Thank you @radiant depot & @gusty salmon !

.solved