Riemann_plus_Riemann(const Riemann_Expr< A, T, Dim, i, j, k, l > &a, const Riemann_Expr< B, U, Dim, i, j, k, l > &b)
Ddg_Expr< Ddg_plus_Ddg< A, B, T, U, Dim01_0, Dim23_0, Dim01_1, Dim23_1, i0, j0, k0, l0, i1, j1, k1, l1 >, typename promote< T, U >::V, Dim01_0, Dim23_0, i0, j0, k0, l0 > operator+(const Ddg_Expr< A, T, Dim01_0, Dim23_0, i0, j0, k0, l0 > &a, const Ddg_Expr< B, U, Dim01_1, Dim23_1, i1, j1, k1, l1 > &b)