NCBorderVectorGather[alist,varlist]

Aliases: None.

Description: NCBorderVectorGather[alist,varlist] can be used to gather the polynomial coefficents preceeding the elements given in varlist whenever they occur in alist. That is to say, alist is a vector with variable entries. Each entry should end with some term from varlist (or the transpose of some term from varlist). Then for each element of varlist the coefficients that appear in front of that element in alist are gathered together and placed inside a list. The list returned will be a list of lists, each entry a list of the coefficients corresponding to the respective entries in varlist and their transposes if they occur.

Arguments: The first argument alist is a list of polynomials, all of which end in terms from elements of the second argument, varlist, or in their transpose. alist need not be ordered in a particular way with respect to varlist. The preceeding is best explained in the following example.
Suppose $List =$

$$\{A**B**k,B**B**tp[h],B**tp[A]**k,B**C**tp[h], A**tp[h],B**h,C**h \}$$

Then NCBorderVectorGather[List,{k,h}] returns the following list

$$\{ \{A**B,B**tp[A]\}, \{B,C\}, \{B**B,B**C,A\} \}$$

Note that the vectors are gather in the pattern $k,tp[k],h,tp[h].$ This pattern will be the same despite the length of avarlist.

Comments / Limitations: None.