FUNCTION: SfA2TableVar - symmetric functions appearing in an expression

CALLING SEQUENCE:

SfA2TableVar(sfa)

SfA2TableVar(sfa, base)

SFA[SfA2TableVar](sfa)

SFA[SfA2TableVar](sfa, base)

PARAMETERS:

sfa = any valid expression in SFA

base = a basis belonging to SFABases

SYNOPSIS:

• The SfA2TableVar function extracts symmetric functions appearing in sfa, and returns a table indexed by each basis b, each entry being itself a table indexed by each alphabet belonging to a b-function. The final entry is the set of indexing vectors of the b-function.

• When a base is specified as second argument, SfA2TableVar only returns the second table corresponding to the b-functions appearing in sfa.

• Whenever there is a conflict between the function name SfA2TableVar and another name used in the same session, use the long form SFA['SfA2TableVar'].

EXAMPLES:

> with(SFA):
> t := SfA2TableVar( q*s[3,2](A1)^2*m[3,1](p[2](A1))-s[2](A1)*h[3,2](k) );
 
               t := table([
                        s = table([
                                A1 = {[2], [3, 2]}
                            ])
                        p = table([
                                A1 = {[2]}
                            ])
                        e =
                        h = table([
                                k = {[3, 2]}
                            ])
                        m = table([
                                p[2](A1) = {[3, 1]}
                            ])
                    ])
 
> t[s][A1];
 
                                 {[2], [3, 2]}
 
> SfA2TableVar( q*s[3,2](A1)^2*m[3,1](p[2](A1)) - s[2](A1)*h[3,2](k), s );
 
                            table([
                                A1 = {[2], [3, 2]}
                            ])