SOLUTION: 1. ~~G 2. (P�Y)v(X->~W) 3. (P�Y)->~G 4. ~W->~G /~X

Algebra.Com
Eval error:

ModPerl::Util::exit: (120000) exit was called at /home/ichudov/project_locations/algebra.com/templates/Algebra/Questions/MoreLikeThis.pm line 159