Homework 2 Errata

• 14.5: This problem is incorrect as stated. In fact, the given strategy profile is NOT an ex-post Nash Equilibrium. I got this problem from a colleague, with whom I have had extensive email correspondence. It turns out that a modified version of this strategy profile is an approximate ex-post Nash Equilibrium in the sense that bidder i can only get a small (additive) advantage by deviating from the prescribed strategy, provided that all other bidders follow the prescribed strategy. A detailed explanation will be given in the solution set for HW2. Because of this error, you will get full credit for your answer to this HW question if you simply provide a correct proof that the prescribed strategy profile is not a dominant-strategy equilibrium. You will get extra credit if you also provide a proof that it is not an ex-post Nash Equilibrium.
• 14.7: There is something missing from this problem as stated: An instance of the interdomain-routing problem should specify the import and export policies of each source AS as well as the AS graph, the destination, the types of the edges, and the valuation functions of the source ASes. Please remember to specify import and export policies.