A binary relation R is reflexive, iff
for all x we have \(xRx\).
The function just checks whether all elements
on the diagonal of B are non-zeros.
is_reflexive(B)object of class igraph or a square
0-1 matrix of class Matrix or matrix
single logical value
Other binary_relations: closure_total_fair;
closure_transitive;
de_transitive;
get_equivalence_classes;
get_incomparable_pairs;
get_independent_sets;
is_total; is_transitive;
pord_weakdom; rel_graph