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7.7.1.0. pIntersectSyz
Procedure from library bfun.lib (see bfun_lib).
- Usage:
- pIntersectSyz(f, I [,p,s,t]); f poly, I ideal, p,t optial ints, p prime
- Return:
- vector, coefficient vector of the monic polynomial
- Purpose:
- compute the intersection of an ideal I with the subalgebra K[f]
- Assume:
- I is given as Groebner basis.
- Note:
- If the intersection is zero, this procedure might not terminate.
If p>0 is given, this proc computes the generator of the intersection in
char p first and then only searches for a generator of the obtained
degree in the basering. Otherwise, it searches for all degrees by
computing syzygies.
If s<>0, std is used for Groebner basis computations in char 0,
otherwise, and by default, slimgb is used.
If t<>0 and by default, std is used for Groebner basis
computations in char >0, otherwise, slimgb is used.
- Display:
- If printlevel=1, progress debug messages will be printed,
if printlevel>=2, all the debug messages will be printed.
Example:
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