Kim, Do-Hyung; Kim, Byung Hak On null cut points in two-dimensional spacetimes. (English) Zbl 1283.53023 Bull. Korean Math. Soc. 50, No. 2, 441-444 (2013). Conjugate points and cut points play an important role in singularity theory and causality theory.There are no null conjugate points in two-dimensional space-times, however, there exists a two-dimensional space-time in which every null geodesic has cut points. This space-time has compact Cauchy surfaces.In the paper it is shown that for two-dimensional Lorentzian manifolds with noncompact Cauchy surfaces there exist no cut points along null geodesics. Reviewer: Zdeněk Dušek (Hradec Kralove) MSC: 53B30 Local differential geometry of Lorentz metrics, indefinite metrics 53C50 Global differential geometry of Lorentz manifolds, manifolds with indefinite metrics Keywords:causality; singularity theory; cut points; conjugate points; Cauchy surface PDFBibTeX XMLCite \textit{D.-H. Kim} and \textit{B. H. Kim}, Bull. Korean Math. Soc. 50, No. 2, 441--444 (2013; Zbl 1283.53023) Full Text: DOI Link