Two firms, i = 1, 2, produce the same good. Each firm i's cost of producing quantity qi is given by Ci(qi) = qi2.
The market demand is given by Pd(Q) = a - Q for all Q = q1 +q2 ≤ a (with Pd(Q) = 0 for all Q>a).
(a) Assume that the two firms choose their quantities simultaneously. Find the Nash equilibrium.
(b) Assume that the two firms choose their quantities sequentially. Find the subgame perfect equilibrium.