Hi, thanks for the reply.

I've tried what you sugested, but had some problems. The line:

Y[3]:=Change(Y[3],{sigma1=z1,sigma2=z1+z2});

doesn't work because Y[3] was assigned as an operator. Therefore, I modfied your code for

Y[3]:=Change(Y[3](omega),{sigma1=z1,sigma2=z1+z2});

then tried to run other lines. The problem is that this last Change operation caused Y[3] to turn into an expression. Thus, Y[5] looks "weird" when I assign it:

Int(Int(H(sigma1)*X(sigma1)*H(sigma5-sigma1)*X(sigma5-sigma1),sigma1)*Int(Int(H(omega-z1-z2)*X(omega-z1-z2)*H(z1)*X(z1)*H(z2)*X(z2),z1),z2)(omega-sigma5),sigma5)

By weird I mean the (omega-sigma5) term near the end of the expression. In the last two integrals, it was supposed to be in the place of omega in the integrand. However, if I maintain the operator form, Maple seems to be unable to make the change of variables they I way I wanted (keeps getting the error I mentioned before).

Doing this way the result looks very similar to what I expect to be, so I guess this must be part of the solution.

I'll keep trying. Thanks for the help again.

Hi, thanks for the reply.

I've tried what you sugested, but had some problems. The line:

Y[3]:=Change(Y[3],{sigma1=z1,sigma2=z1+z2});

doesn't work because Y[3] was assigned as an operator. Therefore, I modfied your code for

Y[3]:=Change(Y[3](omega),{sigma1=z1,sigma2=z1+z2});

then tried to run other lines. The problem is that this last Change operation caused Y[3] to turn into an expression. Thus, Y[5] looks "weird" when I assign it:

Int(Int(H(sigma1)*X(sigma1)*H(sigma5-sigma1)*X(sigma5-sigma1),sigma1)*Int(Int(H(omega-z1-z2)*X(omega-z1-z2)*H(z1)*X(z1)*H(z2)*X(z2),z1),z2)(omega-sigma5),sigma5)

By weird I mean the (omega-sigma5) term near the end of the expression. In the last two integrals, it was supposed to be in the place of omega in the integrand. However, if I maintain the operator form, Maple seems to be unable to make the change of variables they I way I wanted (keeps getting the error I mentioned before).

Doing this way the result looks very similar to what I expect to be, so I guess this must be part of the solution.

I'll keep trying. Thanks for the help again.