IB000/helpers/uzavery.php: base of Relation is a Set
IB000/helpers/uzavery.php: faster transitiveClosure
IB000/helpers/uzavery.php: refactored createFromMany
IB000/helpers/uzavery.php: createCartesianProduct
IB000/helpers/uzavery.php: anti-symetric in test()
IB000/helpers/uzavery.php: printPairs is 2D !
IB000/helpers/uzavery.php: solving of pupils in classroom
IB000/helpers/uzavery.php: better example for transitiveClosure
IB000/helpers/uzavery.php: better example for solving classroom member relations