Denoting a linear differential operator of a nonlinear partial differential equation that a physical quantity U should satisfy as A, a nonlinear differential operator as B, and a nonhomogeneous term (source term) as (f), A.U+B(U)=f is solved by a successive approximationmethod. 物理量Uが満たすべき非線形偏微分方程式の線形微分演算子をA,非線形微分演算子をB、非斉次項(ソース項)をfとしたとき、A・U+B(U)=fを逐次近似法を用いて解く。 - 特許庁