mark_core: Marking nodes as core or periphery

In netrics: Many Ways to Measure and Classify Membership for Networks, Nodes, and Ties

Marking nodes as core or periphery

Description

node_is_core() identifies whether nodes belong to the core of the network, as opposed to the periphery.

Usage

node_is_core(.data, centrality = c("degree", "eigenvector"))

Arguments

.data	A network object of class mnet, igraph, tbl_graph, network, or similar. For more information on the standard coercion possible, see manynet::as_tidygraph().
centrality	Which centrality measure to use to identify cores and periphery. By default this is "degree", which relies on the heuristic that high degree nodes are more likely to be in the core. An alternative is "eigenvector", which instead begins with high eigenvector nodes. Other methods, such as a genetic algorithm, CONCOR, and Rombach-Porter, can be added if there is interest.

Value

A node_mark logical vector the length of the nodes in the network, giving either TRUE or FALSE for each node depending on whether the condition is matched.

Core-periphery

This function is used to identify which nodes should belong to the core, and which to the periphery. It seeks to minimize the following quantity:

Z(S_1) = \sum_{(i<j)\in S_1} \textbf{I}_{\{A_{ij}=0\}} + \sum_{(i<j)\notin S_1} \textbf{I}_{\{A_{ij}=1\}}

where nodes \{i,j,...,n\} are ordered in descending degree, A is the adjacency matrix, and the indicator function is 1 if the predicate is true or 0 otherwise. Note that minimising this quantity maximises density in the core block and minimises density in the periphery block; it ignores ties between these blocks.

References

On core-periphery partitioning

Borgatti, Stephen P., & Everett, Martin G. 1999. "Models of core /periphery structures". Social Networks, 21, 375–395. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1016/S0378-8733(99)00019-2")}

Lip, Sean Z. W. 2011. “A Fast Algorithm for the Discrete Core/Periphery Bipartitioning Problem.” \Sexpr[results=rd]{tools:::Rd_expr_doi("10.48550/arXiv.1102.5511")}

See Also

Other core-periphery: measure_core, member_core

Other marks: mark_degree, mark_diff, mark_dyads, mark_nodes, mark_select_node, mark_select_tie, mark_ties, mark_triangles

Other nodal: mark_degree, mark_diff, mark_nodes, mark_select_node, measure_assort_node, measure_broker_node, measure_brokerage, measure_central_between, measure_central_close, measure_central_degree, measure_central_eigen, measure_closure_node, measure_core, measure_diffusion_node, measure_diverse_node, member_brokerage, member_cliques, member_community, member_community_hier, member_community_non, member_components, member_core, member_diffusion, member_equivalence, motif_brokerage_node, motif_exposure, motif_node, motif_path

Examples

node_is_core(ison_adolescents)
ison_adolescents |> 
   mutate(corep = node_is_core())

netrics documentation built on July 24, 2026, 5:07 p.m.