MathPHP\SetTheory\Set::powerSet PHP Méthode

    public function powerSet() : Set
    {
        // Setup
        $n = count($this->A);
        // Size of the original set
        $２ⁿ = pow(2, $n);
        // Size of the power set
        $A = array_values($this->A);
        //  Original set as an array with numbered indices
        $P⟮S⟯ = new Set();
        //  Power set to be created
        // Populate power set
        for ($i = 0; $i < $２ⁿ; $i++) {
            $member_set = new Set();
            for ($j = 0; $j < $n; $j++) {
                if ($i & 1 << $j) {
                    $member_set->add($A[$j]);
                }
            }
            $P⟮S⟯->add($member_set);
        }
        return $P⟮S⟯;
    }

 /**
  * @dataProvider dataProviderForPowerSet
  */
 public function testPowerSet(Set $A, Set $expected)
 {
     $P⟮S⟯ = $A->powerSet();
     $this->assertEquals($expected, $P⟮S⟯);
     $this->assertEquals($expected->asArray(), $P⟮S⟯->asArray());
     $this->assertEquals(count($expected), count($P⟮S⟯));
 }