lass="intersentencespace"></span> A set is a collection of items of the same kind.<span class="intersentencespace"></span> Each collection has a name and a precise definition for which items belong in that collection.<span class="intersentencespace"></span> Note also that each of the sets in the list contains all the sets above it, as illustrated in <a href="01_math_fundamentals_fragment.html#fig-nested_sets" class="hyperref">Figure <span class="ref">1.2</span></a>.<span class="intersentencespace"></span> 