The co-rank of a graph 
is defined as 
,
where 
is the number of edges of 
,
is the number of vertices, and 
is the number of connected components (Biggs 1993, p. 25).
Graph Co-Rank
See also
Graph Rank, Rank PolynomialExplore with Wolfram|Alpha
References
Biggs, N. L. Algebraic Graph Theory, 2nd ed. Cambridge, England: Cambridge University Press, p. 25, 1993.Godsil, C. and Royle, G. Algebraic Graph Theory. New York: Springer-Verlag, 2001.Referenced on Wolfram|Alpha
Graph Co-RankCite this as:
Weisstein, Eric W. "Graph Co-Rank." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/GraphCo-Rank.html