Some effects of property N-p on the higher normality and defining equations of nonlinearly normal varieties

摘要

For a smooth projective variety X subset of P-r embedded by the complete linear system, Property N-p has been studied for a long time ([5], [11], [12], [7] etc.). On the other hand, Castelnuovo-Mumford regularity conjecture and related problems have been focused for a projective variety which is not necessarily linearly normal ([2], [13], [15], [17], [20] etc.). This paper aims to explain the influence of Property N-p on higher normality and defining equations of a smooth variety embedded by a sub-linear system. Also we prove a claim about Property N-p of surface scrolls which is a generalization of Green's work in [11] about Property N-p for curves.