Atindogbe, C.Gutiérrez, M.Hounnonkpe, R.2022-04-202022-04-202019C. Atindogbe, M. Gutiérrez, R. Hounnonkpe. (2019). Functions of time type, curvature and causality theory. Pg 114-124https://doi.org/10.1016/j.difgeo.2019.02.006http://hdl.handle.net/123456789/1407Causality theory is a well established subject in Lorentzian manifolds and its importance is widely recognized. There are nice results where the levels of the causal ladder can be deduced starting from various assumptions.In the present paper various necessary and/or sufficient conditions in terms of the existence and properties of quasi-time functions, semi-time functions and generalized time functions are provided to get different levels of the causal ladder in spacetimes. We also show several links between curvature conditions and causality.enCasualityCasual hierarchyGeneralized time functionQuasi-time functionSemi-time functionNull convergence conditionArticle