Gluing of Lorentzian length spaces and the causal ladder

Abstract We investigate the compatibility of Lorentzian amalgamation with various properties of Lorentzian pre-length spaces. In particular, we give conditions under which gluing of Lorentzian length spaces yields again a Lorentzian length space and we give criteria which preserve many steps of the causal ladder. We conclude with some thoughts on the causal properties which seem not so easily transferable.