Optimal control and calculus of variation
LetF
t,x,x
be a kernel for a calculus of variation problem. In this case
H=F(t,x,u)+pu.
By the optimality conditionHu= 0 =Fu^0 +pthat is
Fu^0 =Fx^0 = p, p= Hx^0 = Fx^0
That is
d
dtF
^0
x=
d
dtp=H
x^0 =Fx^0.