Use this if you are using igraph from R
The k-core of graph is a maximal subgraph in which each vertex has at least degree k. The coreness of a vertex is k if it belongs to the k-core but not to the (k+1)-core.
coreness(graph, mode = c("all", "out", "in"))
The input graph, it can be directed or undirected
The type of the core in directed graphs. Character constant,
The k-core of a graph is the maximal subgraph in which every vertex has at least degree k. The cores of a graph form layers: the (k+1)-core is always a subgraph of the k-core.
This function calculates the coreness for each vertex.
Numeric vector of integer numbers giving the coreness of each vertex.
Gabor Csardi firstname.lastname@example.org
Vladimir Batagelj, Matjaz Zaversnik: An O(m) Algorithm for Cores Decomposition of Networks, 2002
Seidman S. B. (1983) Network structure and minimum degree, Social Networks, 5, 269–287.
g <- make_ring(10) g <- add_edges(g, c(1,2, 2,3, 1,3)) coreness(g) # small core triangle in a ring