Factoring for quadractics of 1 or 2 variables seems to be correctly enforced

by PolynomialFactors-Strict context.

However, polynomials with 4 variables seems to not have factoring enforced.

See below.

If you submit your answer as a*c + a*d + b*c + b*d

it is accepted.

DOCUMENT();

loadMacros(

"PGstandard.pl",

"PGML.pl",

"MathObjects.pl",

"PGcourse.pl",

"parserNumberWithUnits.pl",

"contextArbitraryString.pl",

"contextPolynomialFactors.pl",

"contextLimitedPowers.pl",

"parserPopUp.pl",

);

TEXT(beginproblem());

$showPartialCorrectAnswers = 1;

######################################################################

Context("PolynomialFactors-Strict");

Context()->flags->set(singleFactors=>0);

LimitedPowers::OnlyIntegers(minPower => 0, maxPower => 1);

Context()->variables->add(a => "Real");

Context()->variables->add(b => "Real");

Context()->variables->add(c => "Real");

Context()->variables->add(d => "Real");

BEGIN_PGML

Write

[`ac + ad + bc + bd`]

in completely factored form.

[________________________]{"(a + b)*(c + d)"}

END_PGML

######################################################################

ENDDOCUMENT();