## WeBWorK Problems

### Re: Empty Set as Student Answer

by Davide Cervone -
Number of replies: 0
OK, you left out of your original message the crucial information that you had redefined the open brace using
   Context()->parens->replace('{' => {close => '}', type => 'Set'});

which is the source of the problem. You want
   Context()->parens->replace('{' => {close => '}', type => 'Set', emptyOK=>1});

to allow empty braces to be allowed.

I'm not sure why you are redefining the braces, ass this new definition (with emptyOK should be exactly what is already in the Interval context, so I'd recommend removing the line entirely. If you way what you are trying to accomplish, I may be able to suggest an alternative.