For a general dynamic system: dXi/dt = Fi(X1, X2,...,Xn), i=1,...,n,
Q.1
do you have some ideas of the existence conditions of following PDE:
a) (grad U, grad U + F) = 0 in n-dimension domain, (,) is inner product;
b) U >=0
Does it need a first type or second type of boundary...