ex series(const relational & s, int order, unsigned options = 0) const;
ex normal(lst &sym_lst, lst &repl_lst, int level = 0) const;
ex to_rational(lst &repl_lst) const;
- ex subs(const lst & ls, const lst & lr) const;
protected:
ex derivative(const symbol & s) const;
int compare_same_type(const basic & other) const;