Add

Response functions can be summed using “+”

Example.Quanty

a1 = {0, -1,-0.5, 0  }
b1 = {  0.1, 0.1, 0.1}
G1 = ResponseFunction.New( {a1,b1,mu=0,type="ListOfPoles", name="G1"} )
 
a2 = {0, 0.5,  1,  1.5}
b2 = {   0.1, 0.1, 0.1}
G2 = ResponseFunction.New( {a2,b2,mu=0,type="ListOfPoles", name="G2"} )
 
G = G1 + G2
 
print("The response function of G is")
print(G)
omega = 1.1
Gamma = 0.001
print()
print("Evaluated at omega =",omega," and Gamma =",Gamma," yields\nG (",G(omega,Gamma),") = G1 (",G1(omega,Gamma),") + G2(",G2(omega,Gamma),")")

yields the output

The response function of G is
{ { 0 , -1 , -0.5 , 0 , 0.5 , 1 , 1.5 } , 
  { 0.1 , 0.1 , 0.1 , 0.1 , 0.1 , 0.1 } ,
  name = G1 ,
  mu = 0 ,
  type = ListOfPoles }

Evaluated at omega =	1.1	 and Gamma =	0.001	 yields
G (	(1.1176700531176 - 0.0055234547287253 I)	) = G1 (	(0.20102811094226 - 7.2191421442561e-05 I)	) + G2(	(0.91664194217538 - 0.0054512633072828 I)	)