& := & \_[ ]{}\
& & -4\_[(1,0)]{}\_[(3,0)]{}T-3\^2\_[(2,0)]{}T -6\^2\_[(1,0)]{}\_[(2,0)]{}T-\^4\_[(1,0)]{}T,\
\_[(3,1)]{}T & := & \_\
& & -3\_[[(1,0)]{}]{}\_[[(2,1)]{}]{}T -\_[[(0,1)]{}]{}\_[[(3,0)]{}]{}T-3\_4\_[[(2,0)]{}]{}\_[[(1,1)]{}]{}T -3\_5\_[[(1,1)]{}]{}\_[[(2,0)]{}]{}T\
& & -3\^2\_[[(1,0)]{}]{}\_[[(1,1)]{}]{}T -3(\_0\_[[(1,0)]{}]{}\_[[(0,1)]{}]{}T +\_1\_[[(0,1)]{}]{}\_[[(1,0)]{}]{})\_[[(2,0)]{}]{}T\
& & -(\_1-\_2-\_6)\_[[(0,1)]{}]{}\^3\_[[(1,0)]{}]{}T -3\_6\_[[(1,0)]{}]{}\_[[(0,1)]{}]{}\^2\_[[(1,0)]{}]{}T\
& & -3(\_2-\_6)\^2\_[[(1,0)]{}]{}\_[[(0,1)]{}]{}\_[[(1,0)]{}]{}T -(\_0-2\_2+\_6)\^3\_[[(1,0)]{}]{}\_[[(0,1)]{}]{}T ,\
\_[(2,2)]{}T & := & \_\
& & -2\_[[(1,0)]{}]{}\_[[(1,2)]{}]{}T+2\_[[(0,1)]{}]{}\_[[(2,1)]{}]{}T- 2\^2\_[[(1,1)]{}]{}T\
& & -\_7\_[[(2,0)]{}]{}\_[[(0,2)]{}]{}T -\_8\_[[(0,2)]{}]{}\_[[(2,0)]{}]{}T - \^2\_[[(1,0)]{}]{}\_[[(0,2)]{}]{}T-\^2\_[[(0,1)]{}]{}\_[[(2,0)]{}]{}T\
& & -4(\_0\_[[(1,0)]{}]{}\_[[(0,1)]{}]{}T+ \_1\_[[(0,1)]{}]{}\_[[(1,0)]{}]{})\_[[(1,1)]{}]{}T\
& & +(\_3+\_2-\_1+\_9) \^2\_[[(0,1)]{}]{}\^2\_[[(1,0)]{}]{}T +(\_3+\_2-\_0-\_9) \^2\_[[(1,0)]{}]{}\^2\_[[(0,1)]{}]{}T\
& & -2(\_3+\_2-\_0\_1-\_9) \_[[(1,0)]{}]{}\_[[(0,1)]{}]{}\_[[(1,0)]{}]{}\_[[(0,1)]{}]{}T\
& & -2(\_3+\_2-\_0\_1+\_9) \_[[(0,1)]{}]{}\_[[(1,0)]{}]{}\_[[(0,1)]{}]{}\_[[(1,0)]{}]{}T\
& & +2(\_3-\_0\_1) \_[[(1,0)]{}]{}\^2\_[[(0,1)]{}]{}\_[[(1,0)]{}]{}T +2(\_2-\_0\_1) \_[[(0,1)]{}]{}\^2\_[[(1,0)]{}]{}\_[[(0,1)]{}]{}T ,\
\_[(1,3)]{}T & := & \_\
& & -3\_[[(0,1)]{}]{}\_[[(1,2)]{}]{}T -\_[[(1,0)]{}]{}\_[[(0,3)]{}]{}T-3\_[10]{}\_[[(0,2)]{}]{}\_[[(1,1)]{}]{}T -3\_[11]{}\_[[(1,1)]{}]{}\_[[(0,2)]{}]{}T\
& & -3\^2\_[[(0,1)]{}]{}\_[[(1,1)]{}]{}T -3(\_0\_[[(1,0)]{}]{}\_[[(0,1)]{}]{}T+ \_1\_[[(0,1)]{}]{}\_[[(1,0)]{}]{})\_[[(0,2)]{}]{}T\
& & -(\_0-\_3-\_[12]{})\_[[(1,0)]{}]{}\^3\_[[(0,1)]{}]{}T -3\_[12]{}\_[[(0,1)]{}]{}\_[[(1,0)]{}]{}\^2\_[[(0,1)]{}]{}T\
& & -3(\_3-\_[12]{})\^2\_[[(0,1)]{}]{}\_[[(1,0)]{}]{} \_[[(0,1)]{}]{}T-(\_1-2\_3+\_[12]{})\^3\_[[(0,1)]{}]{} \_[[(1,0)]{}]{}T ,\
\_[(0,4)]{}T & := & \_[ ]{}\
& & -4\_[(0,1)]{}\_[(0,3)]{}T-3\^2\_[(0,2)]{}T -6\^2\_[(0,1)]{}\_[(0,2)]{}T-\^4\_[(0,1)]{}T, \[operator04\] where the quantities $\epsilon_A$ ($A=0,\dots,12$) are real numbers which must satisfy the following conditions \_0+\_1 = 1,    \_4+\_5 = 1,     \_7+\_8 = 1,     \_[10]{}+\_[11]{} = 1. \[constraints\] These constants reflect the fact that, as already mentioned above, there is not a unique way of constructing an expansion of the type (\[mainidea\]), actually the number of possibilities is infinite. In this paper we have restricted ourselves to expansions in which every single term has the form $\cL_{(p_1,q_1)}\cdots\cL_{(p_n,q_n)}T$ with $p_1+q_1 \leq \cdots \leq p_n+q_n$. Then, the constants $\epsilon_A$ express the freedom that we 