1. [10 marks] CRR model: European contingent claim. Consider the CRR model M = (B, S) with the horizon date T = 2, the interest rate r = 0.2, and the stock price S0 = 80, S_1^u = 104, S_1^d = 88. Let X be the European contingent claim maturing at T = 2 with the payoff given by the following expression with K = 116
X = |S2 - K|1_{|S2 - K|>10} = { |S2 - K|, on the event {|S2 - K| > 10}, 0, on the event {|S2 - K| ≤ 10}.
(a) Find the parameters u and d, compute the stock price at time t = 2, and find the risk-neutral probability P.
(b) Compute the arbitrage price of X using the risk-neutral valuation formula πt(X) = Bt Ep(X B_T^-1 | Ft), t = 0, 1, 2.
(c) Find the replicating strategy φ1 = (φ_1^0, φ_1^1) at time t = 1 for the claim X and check that V1(φ) = π1(X).
(d) Find the replicating strategy φ0 = (φ_0^0, φ_0^1) at time t = 0 for the claim X and check that V0(φ) = π0(X).
(e) Show that the following equality is always satisfied in the CRR model (do not use numbers to derive this equality)
Ep(S2 - S1) = r(1 + r)S0. (1)
Compute the price of Y = |S2 - S1| at time 0 using equation (1).