@Kitonum When this error is appear usually?

@Kitonum I used from your short procedure in my implementation. In the middle of running of my implementation appears the following error where is related with your short procedure. The error is

"Error, (in unknown) invalid input: `expand/power` uses a 2nd argument, e, which is missing"

In fact at the middle of my implementation the input of your short procedure is

A=

B=

If I use from your short proc for these inputs seperatly, it work correctly but, in the middle of run, when program call your short proc, the above error is appeared. What is problem?

@Kitonum Is this a general method?

@Markiyan Hirnyk But your input is two list. I want C only.

@Kitonum Thanks but I want a general method.

@roman_pearce I want not happend this error in the running of my algorithm. What I have to do?

@Kitonum 

lt(p,T)=LeadingCoefficient(p,T)*LeadingTerm(p,T). Is there any question?

@Kitonum 

I think that the coeffs command use from my procedure.

@asa12 

There is a minor fault in the answer of Carl. For example if p=x^2 then by using Maple 14 we have

[op(p)]=[x,2]!!

For this simple question I implement the following procedure: In this procedure f is a polynomial and T is a monomial ordering such as lex or tdeg ordering.

FL := proc (f, T)
local L, p;
L := [];
p := f;
while p <> 0 do
    L := [op(L), lt(p, T)];
    p := simplify(p-lt(p, T))
end do;
RETURN(L)
end proc:

FL(x^2,plex(x))=[x^2]

FL(1+xy-x^2,plex(x))=[1,xy,x^2]

@Carl Love Thank you for this replying.

@Carl Love What is debug? I don't understand your idea. Could you please send me a Maple sheet contained your idea (running the debug)?

@Carl Love I think that eliminate command use from grobner basis also. Do you know its algorithm?

@Carl Love I don't know why you ask my title? I study Grobner basis and comprehensive grobner basis.
What is your idea about my procedure?

@Carl Love I don't know how you deduce that my reply is rude and evasive! I study some topics in Grobner basis and if I yield new results I will thank MaplePrime and especially you.
If you are sad I don't ask any question from now?

@Axel Vogt This is a little part of my main project.