without specify the characteristic,

what is the default characteristic used in hilbert series?

I have a new question here about using maple, welcome to answer

http://math.stackexchange.com/questions/1049655/how-to-calculate-a-in-this-description

if given a prime ideal p, is it possible to find back possible ideal A which output this prime ideal

such that p*A = 0

http://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1001&context=math_etds

Example 3.23 in page 24

degree(2*z^2 + z + 2); #2

how to convert rational function to into (something) - (something) + (something) like in the example

the example 's rational function is 2*z^2+z+2

if rational function is has denominator how to calculate?

2z^2 + z + 2 =

z+2
3


−

z−2
3


+

z+1
2


−

z−4
2


+

z
1


−

z−8
1

when calculate delta p1, what is bi? how to calculate like the example's one?

(z+i-1 i+1-j) - (z+i-bi-1 i+1-1)

sum(d,i=j) (z+i-1 i+1-j) - (z+i-bi-1 i+1-1)

3.23
(z 1) - (z-bi 1)

how to do the expansion in step 3, as i use right shift that can not calculate the same result as in the example.

x0*x1/x0 = x1; # not same as in the example for I

x1^4*x2/x1 = x2*x1^3;  # not same as in the example for I

finally would like to apply to hilbert series 1/((1+z)*(1+z^2))

i use a not good example's polynomials to illustrate the idea

u1:=3*a*c+b^2+c;
u2:=7*a^5*b*c^3;
u3:=a+3*b^2;
T := lexdeg([a,b,c],[e1,e2, e3]);
GB := Basis([e1-u1, e2-u2, e3-u3],T);
result := NormalForm(a*b+b*c, GB, T);

now result is to express a*b+b*c in terms of e1, e2, e3 which represent u1, u2, u3.

is it possible to use preimage to find possible u1,u2,u3 if unknown u1,u2,u3 and given known eqx?

How to use preimage to find possible eqx if given known u1,u2,u3 to find eqx in NormalForm(eqx, GB, T)?

what i confused in code below is that if i know it in terms of -1*e1+2*e2+*e3

it already can be used to find eqx, it seems reasonable to put source1list as unknown to find eqx  or find unknown eq1, eq2, eq3 if given known eqx.

with(RegularChains):
with(ConstructibleSetTools):
source1 := PolynomialRing([e1, e2, e3]);
target1 := PolynomialRing([a, b, c]);
source1list := [...];
target1list := [eq1, eq2, eq3];
cs := PolynomialMapPreimage(target1list, source1list, source1, target1);
Info(cs, source1);
[[e1-e2-e3], [1]]
-1*eq1+2*eq2+*eq3;