ex eval(int level = 0) const;
ex evalf(int level = 0) const { return *this; } // overwrites basic::evalf() for performance reasons
ex series(const relational & s, int order, unsigned options = 0) const;
ex eval(int level = 0) const;
ex evalf(int level = 0) const { return *this; } // overwrites basic::evalf() for performance reasons
ex series(const relational & s, int order, unsigned options = 0) const;