Power vertex operator

Add a sequence of columns to the power symmetric functions

> CP:=proc(a,k,EX) local n,i,la;
simplify(p.a^k*EX + convert([seq(seq(p.a^(k-nops(la))*convert(
[seq(p.(la[i]+a) - p.(la[i])*p.a,i=1..nops(la))],`*`)*skew(
convert([seq(p.(la[i]),i=1..nops(la))],`*`),EX)/zee(la),la=Par(n,k)),
n=1..`SF/stdeg`(EX))],`+`));
end: