Difference between revisions of "ApCoCoA-1:NC.LC"

From ApCoCoAWiki
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<title>NC.LC</title>
 
<title>NC.LC</title>
 
<short_description>
 
<short_description>
Leading coefficient of a polynomial over a free monoid ring.
+
Leading coefficient of a polynomial in a free monoid ring.
 
</short_description>
 
</short_description>
 
<syntax>
 
<syntax>
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NC.LC(F);
 
NC.LC(F);
 
2
 
2
 
 
-------------------------------
 
-------------------------------
 
NC.SetOrdering(<quotes>LLEX</quotes>);
 
NC.SetOrdering(<quotes>LLEX</quotes>);
 
NC.LC(F);
 
NC.LC(F);
 
4
 
4
 
 
-------------------------------
 
-------------------------------
 
NC.LC([]); -- 0 polynomial
 
NC.LC([]); -- 0 polynomial
 
0
 
0
 
 
-------------------------------
 
-------------------------------
 
</example>
 
</example>
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<see>NC.Interreduction</see>
 
<see>NC.Interreduction</see>
 
<see>NC.Intersection</see>
 
<see>NC.Intersection</see>
 +
<see>NC.IsFinite</see>
 
<see>NC.IsGB</see>
 
<see>NC.IsGB</see>
 
<see>NC.IsHomog</see>
 
<see>NC.IsHomog</see>
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<see>NC.SetX</see>
 
<see>NC.SetX</see>
 
<see>NC.Subtract</see>
 
<see>NC.Subtract</see>
 +
<see>NC.TruncatedGB</see>
 
<see>NC.UnsetFp</see>
 
<see>NC.UnsetFp</see>
 
<see>NC.UnsetOrdering</see>
 
<see>NC.UnsetOrdering</see>

Revision as of 15:34, 8 June 2012

NC.LC

Leading coefficient of a polynomial in a free monoid ring.

Syntax

NC.LC(F:LIST):INT or RAT

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 NC.SetFp, NC.SetX and NC.SetOrdering, respectively, before calling the function. The default coefficient field is Q. The default ordering is length-lexicographic ordering ("LLEX"). For more information, please check the relevant functions.

  • @param F: a polynomial in K<X>. Each polynomial is represented as a LIST of monomials, which are pairs 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 INT or RAT which represents the leading coefficient of F w.r.t. the current ordering. If F=0, the function returns 0.

Example

NC.SetX(<quotes>abc</quotes>);
F:=[[1,<quotes>ab</quotes>],[2,<quotes>aa</quotes>],[3,<quotes>bb</quotes>],[4,<quotes>bab</quotes>]];
NC.SetOrdering(<quotes>ELIM</quotes>);
NC.LC(F);
2
-------------------------------
NC.SetOrdering(<quotes>LLEX</quotes>);
NC.LC(F);
4
-------------------------------
NC.LC([]); -- 0 polynomial
0
-------------------------------

See also

NC.Add

NC.Deg

NC.FindPolynomials

NC.GB

NC.HF

NC.Interreduction

NC.Intersection

NC.IsFinite

NC.IsGB

NC.IsHomog

NC.KernelOfHomomorphism

NC.LC

NC.LT

NC.LTIdeal

NC.MB

NC.MinimalPolynomial

NC.Multiply

NC.NR

NC.ReducedGB

NC.SetFp

NC.SetOrdering

NC.SetRelations

NC.SetRules

NC.SetX

NC.Subtract

NC.TruncatedGB

NC.UnsetFp

NC.UnsetOrdering

NC.UnsetRelations

NC.UnsetRules

NC.UnsetX

Introduction to CoCoAServer