Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
The result of Colombo and Labrecciosa [Colombo, Luca and Labrecciosa, Paola (2006). 'The suboptimality of optimal punishments in Cournot supergames', Economics Letters 90, pp. 116-121.] that optimal punishments are inferior to Nash-reversion trigger strategies with decreasing marginal costs is shown to be due to the output when a firm deviates from the punishment path becoming negative.