MathPHP\SetTheory\SetAxiomsTest::testUnsionAssociative PHP Method

    public function testUnsionAssociative(Set $A, Set $B, Set $C)
    {
        $A∪⟮B∪C⟯ = $A->union($B->union($C));
        $⟮A∪B⟯∪C = $A->union($B)->union($C);
        $this->assertEquals($A∪⟮B∪C⟯, $⟮A∪B⟯∪C);
        $this->assertEquals($A∪⟮B∪C⟯->asArray(), $⟮A∪B⟯∪C->asArray());
    }