This set of functions lets the user query different aspects of the graph itself. They are all concerned with wether the graph implements certain properties and will all return a logical scalar.
graph_is_simple() graph_is_directed() graph_is_bipartite() graph_is_connected() graph_is_tree() graph_is_forest() graph_is_dag() graph_is_chordal() graph_is_complete() graph_is_isomorphic_to(graph, method = "auto", ...) graph_is_subgraph_isomorphic_to(graph, method = "auto", ...)
graph  The graph to compare structure to 

method  The algorithm to use for comparison 
...  Arguments passed on to the comparison methods. See

A logical scalar
graph_is_simple
: Is the graph simple (no parallel edges)
graph_is_directed
: Is the graph directed
graph_is_bipartite
: Is the graph bipartite
graph_is_connected
: Is the graph connected
graph_is_tree
: Is the graph a tree
graph_is_forest
: Is the graph an ensemble of multiple trees
graph_is_dag
: Is the graph a directed acyclic graph
graph_is_chordal
: Is the graph chordal
graph_is_complete
: Is the graph fully connected
graph_is_isomorphic_to
: Is the graph isomorphic to another graph. See igraph::is_isomorphic_to()
graph_is_subgraph_isomorphic_to
: Is the graph an isomorphic subgraph to another graph. see igraph::is_subgraph_isomorphic_to()
#> [1] TRUE