Ein Satz vom Korovkin-Typ f�rC k -R�ume

Approximation of the rth differential operator by means of linear shape preserving operators of finite rank

“…The rank of A is not equal to zero, rank Aa0: Indeed, if rank A ¼ 0; then D r L n f ðz j Þ ¼ P n i¼0 a i ð f ÞD r u i ðz j Þ ¼ 0; j ¼ 0; y; n; for every f AC k ðX Þ; which contradicts hypothesis (2).…”

The Hormonal Regulation of Morphogenesis in Mosses

“…The caulonema is best characterized by a comparison of the walls between the cells in the mament. In every mament tip of primary chloronemata, as well as in "secondary" chloronemata which form as a result of deficiency conditions (40,42), the cell walls are strongly and regularly perpendicular. In caulonemata the walls between the cells are always oblique (Fig.…”