?</a><a id="What-is-a-Matroid?-1"></a><a class="docs-heading-anchor-permalink" href="#What-is-a-Matroid?" title="Permalink"></a></h1><h2 id="Core-Definitions"><a class="docs-heading-anchor" href="#Core-Definitions">Core Definitions</a><a id="Core-Definitions-1"></a><a class="docs-heading-anchor-permalink" href="#Core-Definitions" title="Permalink"></a></h2><p>A <em>matroid</em> is a pair <span>$M=(S,\mathcal{I})$</span> where <span>$S$</span> is a set and <span>$\mathcal{I}$</span> is a set of subsets of <s