THE INTERPOLATION AND APPROXIMATION BY DOUBLE-PERIODIC QUADRATIC SPLINES
双周期二次样条的插值逼近

§1.引言 考虑矩形区域Ω=0,1]?0,1],Δ_(mn)~((2))为Ω的均匀四方向网,它将Ω分成4mn个小三角形单元. 样条空间 S_2~1(Δ_(mn)~((2)))由满足以下条件的S(x,y)组成: