, a multivalued function
is a total relation
; i.e. every input
is associated with one or more outputs. Strictly speaking, a "well-defined" function
associates one, and only one, output
to any particular input
. The term "multivalued function" is, technically, a logical contradiction
" functions are monovalued.
The above diagram does not represent a "true" function; because, the element 3, in X, is associated with two elements b and c, in Y.