부산대학교 도서관

This paper deals with $B$-scrolls, the famous example given by L. K. Graves [Trans. Amer. Math. Soc. {\bf 252} (1979), 367--392; MR0534127 (80j:53060)]. A $B$-scroll is a surface which can be parametrized as a ``ruled surface'' in the Minkowski 3-space $\Bbb{L}^3$ with null directrix curve and null rulings, i.e., $X(s,t) = x(s)+tB(s)$, $x(s)$ being a null curve and $B(s)$ a null vector field along $x(s)$ satisfying $\langle x',B\rangle = -1$. In the paper under review some characterizations and examples of $B$-scrolls are given.