x,
y, z we have $xRy$ and $yRz$ =>
$xRz$is_transitive(B)igraph or a square 0-1
matrix of class Matrix or matrixclosure_total_fair,
closure_transitive,
de_transitive,
get_equivalence_classes,
get_incomparable_pairs,
get_independent_sets,
is_reflexive, is_total,
pord_weakdom, rel_graph