isLocatedAfter(X,Y) : genetic interval X is located after genetic interval Y If genetic interval X is located after genetic interval Y, then the start of X is after the end of Y; or the end of Y is before the start of X. If isLocatedBefore(X,Y), then isLocatedAfter(Y,X) isLocatedAfter(X,Y) ↔ (hasStartPoint(x1,X) & hasEndPoint(y1,Y) & isLocatedAfter(x1,y1)) OR (hasEndPoint(x2,X) &. hasStartPoint(y2,Y) & isLocatedBefore(y2,x2)) isLocatedAfter(X,Y) == isLocatedBefore(Y,X)