Cauchy problem in function spaces with asymptotic expansions with respect to time variable

A system of nonlinear Cauchy problem $\partial_t u_i=f_i(t,x, U, \nabla_xU )$ $u_i(0,x)= u_{i,0}(x)$ is studied in function spaces with asymptotic expansion with respect to $t$. To be specific, it is discussed in Borel summable or multisummable function space.It is recognized that these functions are important classes in asymptotic analysis. We study equations under the condition $\{f_i(t,x, U, P)\}_{i=1}^m$ are in these function spaces with respect to $t$ and show $\{u_i(t,x)\}_{i=1}^m$ have also the same summability.