#ifndef STAN_MATH_FWD_CORE_OPERATOR_SUBTRACTION_HPP
#define STAN_MATH_FWD_CORE_OPERATOR_SUBTRACTION_HPP

#include <stan/math/fwd/core/fvar.hpp>


namespace stan {

  namespace math {

    template <typename T>
    inline
    fvar<T>
    operator-(const fvar<T>& x1, const fvar<T>& x2) {
      return fvar<T>(x1.val_ - x2.val_, x1.d_ - x2.d_);
    }

    template <typename T>
    inline
    fvar<T>
    operator-(const double x1, const fvar<T>& x2) {
      return fvar<T>(x1 - x2.val_, -x2.d_);
    }

    template <typename T>
    inline
    fvar<T>
    operator-(const fvar<T>& x1, const double x2) {
      return fvar<T>(x1.val_ - x2, x1.d_);
    }
  }
}
#endif
