The 
-cores of a graph are the connected
components that remain after all vertices of vertex
degree less than 
have been repeatedly removed.
The largest value 
such that a graph 
has a 
-core is called the graph
degeneracy of 
.
k-Core
See also
Connected Component, Graph Degeneracy, Vertex DegreeExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "k-Core." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/k-Core.html