Difference between revisions of "ApCoCoA-1:NCo.LW"

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<item>@param <em>F</em>: a non-zero polynomial in <tt>K&lt;X&gt;</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>&lt;X&gt;</tt> and C is the coefficient of W. For example, the polynomial <tt>f=xy-y+1</tt> is represented as F:=[[1,<quotes>xy</quotes>], [-1, <quotes>y</quotes>], [1,<quotes></quotes>]]. The zero polynomial <tt>0</tt> is represented as the empty LIST [].</item>
 
<item>@param <em>F</em>: a non-zero polynomial in <tt>K&lt;X&gt;</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>&lt;X&gt;</tt> and C is the coefficient of W. For example, the polynomial <tt>f=xy-y+1</tt> is represented as F:=[[1,<quotes>xy</quotes>], [-1, <quotes>y</quotes>], [1,<quotes></quotes>]]. 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 ordering. If <tt>F=0</tt>, the function returns nothing.</item>
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<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>
 
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Revision as of 16:55, 29 April 2013

NCo.LW

The leading word of a non-zero polynomial in a free monoid ring.

Syntax

NCo.LW(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(<quotes>abc</quotes>);
F:=[[1,<quotes>ab</quotes>],[1,<quotes>aa</quotes>],[1,<quotes>bb</quotes>],[1,<quotes>bab</quotes>]];
NCo.LW(F); -- LLEX ordering (default ordering)
bab
-------------------------------
NCo.SetOrdering(<quotes>ELIM</quotes>);
NCo.LW(F); 
aa
-------------------------------
NCo.LW([]);

See also

NCo.SetFp

NCo.SetOrdering

NCo.SetX

Introduction to CoCoAServer