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<a accesskey="3" href="page.php?w=Hosoya_index&amp;p=2">3.Next</a>
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<p>The <b>Hosoya index</b>, also known as the <b>Z index</b>, of a <a href="page.php?w=Graph_%28discrete_mathematics%29">graph</a> is the total number of <a href="page.php?w=Matching_%28graph_theory%29">matchings</a> in it. The Hosoya index is always at least one, because the <a href="page.php?w=empty_set">empty set</a> of edges is counted as a matching for this purpose. Equivalently, the Hosoya index is the number of non-empty matchings plus one. The index is named after <a href="page.php?w=Haruo_Hosoya">Haruo Hosoya</a>. It is used as a <a href="page.php?w=topological_index">topological index</a></p><p>
<a accesskey="3" href="page.php?w=Hosoya_index&amp;p=2">3.Next</a>
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