1·The operator in parentheses in (3. 54) is. called the Laplacian operator.
在(3.54)的括号里的算符叫做拉普拉斯算符。
2·In this paper we propose so-called coupled 4-point difference schemes for the Laplacian operator over a class of parallel hexagon partitions of the plane.
本文提出平面上拉普拉斯算子在一类平行六边形网格上的成对4点差分格式。