Computing all inferrable relations is impractical. Point algebra (PA) can express each basic Allen relation as a conjunctive set of point-wise relations between the starts and endings of the intervals. For example, $x$ {equals} $y$ can be expressed by the conjunctive set $x^{-}=y^{-}, x^{+}=y^{+}$. They also allow expression of many indefinite relations. Reasoning in PA requires a much smaller transitivity table, which contributes to its efficiency, important for practical TR systems.