+ pos = !pos;
+ else
+ return false;
+ }
+ if (overall_coeff.info(info_flags::negint))
+ pos = !pos;
+ else if (!overall_coeff.info(info_flags::posint))
+ return false;
+ return (inf ==info_flags::posint? pos : !pos);
+ }
+ case info_flags::nonnegint: {
+ bool pos = true;
+ epvector::const_iterator i = seq.begin(), end = seq.end();
+ while (i != end) {
+ const ex& factor = recombine_pair_to_ex(*i++);
+ if (factor.info(info_flags::nonnegint) || factor.info(info_flags::posint))
+ continue;
+ else if (factor.info(info_flags::negint))
+ pos = !pos;