MathPHP\SetTheory\SetAxiomsTest::testACartesianProductWithEmptySetIsEmptySet PHP Метод

    public function testACartesianProductWithEmptySetIsEmptySet(Set $A)
    {
        $Ø = new Set();
        $A×Ø = $A->cartesianProduct($Ø);
        $this->assertEquals($Ø, $A×Ø);
    }