Answer
a. A function F is one-to-one if, and only if, each element
in the co-domain of F is the image of at $MOST$ one
element in the domain of F.
. A function F is onto if, and only if, each element in the
co-domain of F is the image of at $LEAST$ one element
in the domain of F.
Work Step by Step
a. A function F is one-to-one if, and only if, each element
in the co-domain of F is the image of at $MOST$ one
element in the domain of F.
. A function F is onto if, and only if, each element in the
co-domain of F is the image of at $LEAST$ one element
in the domain of F.