Difference between revisions of "ApCoCoA-1:NCo.LW"
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<title>NCo.LW</title> | <title>NCo.LW</title> | ||
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<em>Please note:</em> The function(s) explained on this page is/are using the <em>ApCoCoAServer</em>. You will have to start the ApCoCoAServer in order to use it/them. | <em>Please note:</em> The function(s) explained on this page is/are using the <em>ApCoCoAServer</em>. You will have to start the ApCoCoAServer in order to use it/them. | ||
<par/> | <par/> | ||
| − | Please set ring environment <em>coefficient field</em> <tt> K</tt>, <em>alphabet</em> (or set of indeterminates) <tt>X</tt> and <em>ordering</em> via the functions <ref>ApCoCoA-1:NCo.SetFp|NCo.SetFp</ref>, <ref>ApCoCoA-1:NCo.SetX|NCo.SetX</ref> and <ref>ApCoCoA-1:NCo.SetOrdering|NCo.SetOrdering</ref>, respectively, before using this function. The default coefficient field is <tt>Q</tt>, and the default ordering is the length-lexicographic ordering ( | + | Please set ring environment <em>coefficient field</em> <tt> K</tt>, <em>alphabet</em> (or set of indeterminates) <tt>X</tt> and <em>ordering</em> via the functions <ref>ApCoCoA-1:NCo.SetFp|NCo.SetFp</ref>, <ref>ApCoCoA-1:NCo.SetX|NCo.SetX</ref> and <ref>ApCoCoA-1:NCo.SetOrdering|NCo.SetOrdering</ref>, respectively, before using this function. The default coefficient field is <tt>Q</tt>, and the default ordering is the length-lexicographic ordering ("LLEX"). For more information, please check the relevant functions. |
<itemize> | <itemize> | ||
| − | <item>@param <em>F</em>: a non-zero polynomial in <tt>K<X></tt>. 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 polynomial is represented as a LIST of monomials, which are LISTs of the form [C, W] where W is a word in <tt><X></tt> and C is the coefficient of W. For example, the polynomial <tt>f=xy-y+1</tt> is represented as F:=[[1, | + | <item>@param <em>F</em>: a non-zero polynomial in <tt>K<X></tt>. 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 polynomial is represented as a LIST of monomials, which are LISTs of the form [C, W] where W is a word in <tt><X></tt> and C is the coefficient of W. For example, the polynomial <tt>f=xy-y+1</tt> is represented as F:=[[1,"xy"], [-1, "y"], [1,""]]. The zero polynomial <tt>0</tt> is represented as the empty LIST [].</item> |
<item>@return: a STRING which represents the leading term of F with respect to the current word ordering. If <tt>F=0</tt>, the function returns nothing.</item> | <item>@return: a STRING which represents the leading term of F with respect to the current word ordering. If <tt>F=0</tt>, the function returns nothing.</item> | ||
</itemize> | </itemize> | ||
<example> | <example> | ||
| − | NCo.SetX( | + | NCo.SetX("abc"); |
| − | F:=[[1, | + | F:=[[1,"ab"],[1,"aa"],[1,"bb"],[1,"bab"]]; |
NCo.LW(F); -- LLEX ordering (default ordering) | NCo.LW(F); -- LLEX ordering (default ordering) | ||
bab | bab | ||
------------------------------- | ------------------------------- | ||
| − | NCo.SetOrdering( | + | NCo.SetOrdering("ELIM"); |
NCo.LW(F); | NCo.LW(F); | ||
aa | aa | ||
Latest revision as of 13:40, 29 October 2020
| This article is about a function from ApCoCoA-1. |
NCo.LW
The leading word (or term) of a non-zero polynomial in a free monoid ring.
Syntax
NCo.LW(F:LIST):STRING NCo.LT(F:LIST):STRING
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 set of indeterminates) X and ordering via the functions NCo.SetFp, NCo.SetX and NCo.SetOrdering, respectively, before using this function. The default coefficient field is Q, and the default ordering is the length-lexicographic ordering ("LLEX"). For more information, please check the relevant functions.
@param F: a non-zero polynomial in K<X>. 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 polynomial is represented as a LIST of monomials, which are LISTs of the form [C, W] where W is a word in <X> and C is the coefficient of W. For example, the polynomial f=xy-y+1 is represented as F:=[[1,"xy"], [-1, "y"], [1,""]]. The zero polynomial 0 is represented as the empty LIST [].
@return: a STRING which represents the leading term of F with respect to the current word ordering. If F=0, the function returns nothing.
Example
NCo.SetX("abc");
F:=[[1,"ab"],[1,"aa"],[1,"bb"],[1,"bab"]];
NCo.LW(F); -- LLEX ordering (default ordering)
bab
-------------------------------
NCo.SetOrdering("ELIM");
NCo.LW(F);
aa
-------------------------------
NCo.LW([]);
See also
