Suppose the quadratic program of Exercise 4 is not feasible. In that case one may solve (a) Show...

Suppose the quadratic program of Exercise 4
is not feasible. In that case one may solve

(a)
Show that if d = 0 is a solution, then d is a descent direction for p. (b) If d
= 0 is a solution, show that x is a critical point of p in the sense that for
any d = 0, p(x + αd) > p(x) + o(α).