@Carl Love 

Tanks a lot for your help. I try analitic, and normally, give the same result.

I must to find another theorethical way to the Hamiltonian calculus. All the best!

@Carl Love 

Hi!

> P1 := (4*Q1^3-12*Q1*Q2^2)*pp1+(12*Q1^2*Q2-4*Q2^3)*pp2+(4*Q1*Q3^2-4*Q1*Q4^2+8*Q2*Q3*Q4)*pp3:
> P2 := (4*Q2^3-12*Q1^2*Q2)*pp1+(4*Q1^3-12*Q1*Q2^2)*pp2+(-4*Q2*Q3^2+4*Q2*Q4^2+8*Q1*Q3*Q4)*pp3:
> P3 := (-4*Q3^3+12*Q3*Q4^2)*pp1+(-12*Q3^2*Q4+4*Q4^3)*pp2+(4*Q1^2*Q3-4*Q2^2*Q3+8*Q1*Q2*Q4)*pp3:
> P4 := (-4*Q4^3+12*Q3^2*Q4)*pp1+(-4*Q3^3+12*Q3*Q4^2)*pp2+(-4*Q1^2*Q4+4*Q2^2*Q4+8*Q1*Q2*Q3)*pp3:
> a := P1^2+P2^2+P3^2+P4^2:

I want a in factor.

Many thanks for your help.

@Carl Love 

Thanks, I tried, but do not go.