Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
In repeated normal‐form (simultaneous‐move) games, simple penal codes (Abreu, Journal of Economic Theory 39(1) (1986), 191–225; and Econometrica 56(2) (1988), 383–96) permit an elegant characterization of the set of subgame‐perfect outcomes. We show that in repeated extensive‐form games such a characterization no longer obtains. By means of examples, we identify two types of settings in which a subgame‐perfect outcome may be supported only by a profile with the property that the continuation play after a deviation is tailored not only to the identity of the deviator but also to the nature of the deviation.