# Difference between revisions of "ApCoCoA-1:NC.HF"

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<type>apcocoaserver</type> | <type>apcocoaserver</type> | ||

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+ | <type>ideal</type> | ||

+ | <type>non_commutative</type> | ||

</types> | </types> | ||

− | <key>gbmr. | + | <key>gbmr.hf</key> |

− | <key>NC. | + | <key>NC.hf</key> |

− | <key> | + | <key>hf</key> |

<wiki-category>Package_gbmr</wiki-category> | <wiki-category>Package_gbmr</wiki-category> | ||

</command> | </command> |

## Revision as of 14:52, 14 December 2010

## NC.HF

Hilbert function of `K`-algebra.

### Syntax

NC.HF(Gb:LIST):LIST NC.HF(Gb:LIST, DegreeBound:INT):LIST

### Description

*Please note:* The function(s) explained on this page is/are using the *ApCoCoAServer*. You will have to start the ApCoCoAServer in order to use it/them.

Please set ring environment coefficient field `K`, alphabet (or indeterminates) `X` and ordering through the functions NC.SetFp(Prime), NC.SetX(X) and NC.SetOrdering(Ordering), respectively, before calling the function. Default coefficient field is `Q`. Default ordering is length-lexicographic ordering ("LLEX"). For more information, please check the relevant functions.

@param

*Gb:*a LIST of non-zero polynomials in`K<X>`which is a Groebner basis of (two-sided) ideal generated by Gb. Each polynomial is represented as a LIST of LISTs, which are pairs of form [C, W] where C is a coefficient and W is a word (or term). Each term is represented as a STRING. For example,`xy^2x`is represented as "xyyx", unit is represented as an empty string "". Then, polynomial`F=xy-y+1`is represented as F:=[[1,"xy"], [-1, "y"], [1,""]].`0`polynomial is represented as an empty LIST [].@param

*DegreeBound:*(optional) a positive integer which is a degree bound of Hilbert funtion.@return: a LIST of non-negative integers, which is a list of coefficient of Hilbert function of

`K<X>/(Gb)`.

#### Example

NC.SetX(<quotes>xyzt</quotes>); NC.SetOrdering(<quotes>LLEX</quotes>); Gb:= [[[1, <quotes>yt</quotes>], [-1, <quotes>ty</quotes>]], [[1, <quotes>xt</quotes>], [-1, <quotes>tx</quotes>]], [[1, <quotes>xy</quotes>], [-1, <quotes>ty</quotes>]], [[1, <quotes>xx</quotes>], [-1, <quotes>yx</quotes>]], [[1, <quotes>tyy</quotes>], [-1, <quotes>tty</quotes>]], [[1, <quotes>yyx</quotes>], [-1, <quotes>tyx</quotes>]]]; NC.HF(Gb, 5); [1, 4, 12, 34, 100, 292] -------------------------------

### See also