Changes

|}

|}

For example, let ''X'' = ''Y'' = {0, …, 9} and let ''F'' ⊆ ''X'' × ''Y'' be the 2-adic relation that is depicted in the bigraph below:

For example, let <math>X = Y = \{ 0, \ldots, 9 \}\!</math> and let <math>F \subseteq X \times Y</math> be the 2-adic relation that is depicted in the bigraph below:

{| align="center" cellspacing="6" width="90%"

{| align="center" cellspacing="6" width="90%"

|}

|}

We observe that ''F'' is a function at ''Y'', and we record this fact in either of the manners ''F''&nbsp;:&nbsp;''X''&nbsp;&larr;&nbsp;''Y'' or ''F''&nbsp;:&nbsp;''Y''&nbsp;&rarr;&nbsp;''X''.

We observe that <math>F\!</math> is a function at <math>Y,\!</math> and we record this fact in either of the manners <math>F : X \leftarrow Y</math> or <math>F : Y \to X.</math>

===Commentary Note 11.10===

===Commentary Note 11.10===