return ex_to<basic>(thisexpairseq(vp, overall_coeff));
else if ((options & subs_options::algebraic) && is_exactly_a<mul>(*this))
return static_cast<const mul *>(this)->algebraic_subs_mul(m, options);
return ex_to<basic>(thisexpairseq(vp, overall_coeff));
else if ((options & subs_options::algebraic) && is_exactly_a<mul>(*this))
return static_cast<const mul *>(this)->algebraic_subs_mul(m, options);