Unmatched vertex in a matching
= Unmatched vertex in a matching
= Unmatched vertices in a matching
{synonym}
A <vertex> is an <unmatched vertex in a matching> $M$ if no <edge> of $M$ is incident to it. It is also called free or exposed, always relative to the specified <matching in a graph>: changing $M$ can change which <vertices> are free. The endpoints of an <augmenting path in a matching> must be distinct <unmatched vertices in a matching> before the change.