平行四边形网格上的递归曲面

Recurrence surfaces on the parallelogram mesh

文中利用直积的方法给出了平行四边形网格上递归曲面的定义，并由此引入了Ｌ曲面和Ｗ曲面，得到了Ｌ曲面的求导公式、基底表示、包络定理和把Ｌ曲面表示为等价的Ｂｅｚｉｅｒ曲面的表示公式．最后证明了平行四边形域上Ｗ曲面具有保凸性．

In this paper we present a definition of the recurrence surface on the parallelogram meshby the method of tensor product, and then introduce the L-surface and W-surface. We alsoobtain formulae for derivation, basis function properties, envelope theorems of the L-surfaceand an equivalent representation of the L-surface as Bezier surface.Finally,we prove that theW-surface on the parallelogram have the convexity-preserving.