Suppose, we have a system described by a set of ordinary differential equations. Is it possible to approximate the system with delay differential equations such that the properties of the system is preserved.
CASE 1: dx1/dt = -a*x1 + b*x2
dx2/dt = -k*x2 + k*x1, where a, k=constant, x1, x2: states; x2 is say a 10 min(k=0.1 min^-1) delayed version of x1. Can we approximate the above equation by dx1/dt = -a*x1 + b*x2(t-T), where T:delay parameter
CASE 2: dx1/dt = -a*x1 + b*x2
dx2/dt = -c*x2 + d*x3
dx3/dt = -e*x3 + u, where x1,x2,x3: states, u: input, a,b,c,d,e: constants. Can we approximate these system by delay differential equations.