We investigate differential geometric properties of curves in semi-Euclidean spaces including singular curve with finite multiplicities.
We introduce the notion of light-like subspace and show that geometric framework are similar to Euclidean case, if all the osculating subspaces are not light-like.
We also discuss several phenomena when some of them are light-like.
福井教授是日本数学会代议员,曾任日本数学会广报委员会委员长,是我校的客座教授,也是国际奇点理论界的权威,已在国际数学顶级杂志《Invent. Math.》、《Topology》等发表30余篇高质量论文。