A near-perfect matching is a matching in which a single vertex is left unmatched. Just as perfect matchings can occur only for graphs with an even number of vertices, near-perfect matchings can occur only for graphs with an odd number of vertices.
Near-Perfect Matching
See also
Matching, Perfect MatchingExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Near-Perfect Matching." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Near-PerfectMatching.html