has continuant part at some time has continuant part at all times that part exists continuant fiat boundary one-dimensional continuant fiat boundary OneDimensionalContinuantFiatBoundary (iff (OneDimensionalContinuantFiatBoundary a) (and (ContinuantFiatBoundary a) (exists (b) (and (OneDimensionalSpatialRegion b) (forall (t) (locatedInAt a b t)))))) // axiom label in BFO2 CLIF: [032-001] 1d-cf-boundary The Equator a one-dimensional continuant fiat boundary is a continuous fiat line whose location is defined in relation to some material entity. (axiom label in BFO2 Reference: [032-001]) all geopolitical boundaries all lines of latitude and longitude the line separating the outer surface of the mucosa of the lower lip from the outer surface of the skin of the chin. the median sulcus of your tongue two-dimensional continuant fiat boundary