Alternating bid bargaining with a smallest money unit

In a seminal paper, Ariel Rubinstein has shown that impatience implies determinateness of the two-person bargaining problem. In this note we show that this result depends also on the assumption that the set of alternatives is a continuum. If the pie can be divided only in finitely many different ways (for example, because the pie is an amount of money and there is a smallest money unit), any partition can be obtained as the result of a subgame perfect equilibrium if the time interval between successive offers is sufficiently small. We also show that, for a fixed discount rate, all subgame perfect equilibrium payoffs of the discrete game converge to the solution obtained by Rubinstein if the smallest money unit tends to zero.