Question: More on complicated substitution with summation and high order polynomials

Hi,

Following the question here,

http://www.mapleprimes.com/questions/150429-Solving-High-Order-Polynomials-with-Summation#comment150438

I now have more complicated substitution to do. Hopefully Maple can achieve it.

See worksheet ask.zip

"kappa" is a complicated expression.

sstest(4,2) give a reparameterisation using 11 terms, s1 to s11.

We were able to substitute it perfectly using

sskappa( sstest(4,2) , kappa );

sstest3(4,2) give a reparameterisation using 10 terms, s1 to s10. (built on sstest(4,2) )

I wonder if we can substitute in a "simpler" way.

If my coding is correct, the "expected" simplified version using sstest3(4,2) would be the same as equation (7) in the worksheet, using,

sskappa( sstest(4,2) , kappa );

ssTwoStage(%,4);

It would be nice to do it just once as i have a lot to substitute.

Casper