Geach Axiom
Modal logic axiom extending S4. Gives you the light-cone - i.e. causal arrows between points in space-time. benthemmodal2010, p97, is where I first came across it; proved in goldblattDiodoreanModalityMinkowski1980
Modal logic axiom extending S4. Gives you the light-cone - i.e. causal arrows between points in space-time. benthemmodal2010, p97, is where I first came across it; proved in goldblattDiodoreanModalityMinkowski1980