# Library Exercise_3_3_1_10

## Problem

A graph is a pair of functions

E ⇉ V. This sets up the notion
of equalizer and coequalizer (see Definitions 2.5.3.1 and
2.6.3.1). What feature of a graph is captured by the equalizer
of its source and target functions? What feature of a graph is
captured by the coequalizer of its source and target functions?