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

From ApCoCoAWiki
(New page: <command> <title>NC.Subtract</title> <short_description> Subtraction of two polynomials in a non-commutative polynomial ring. </short_description> <syntax> NC.Sub(F1:LIST, F2:LIST):LIST </...)
 
Line 1: Line 1:
 
<command>
 
<command>
<title>NC.Subtract</title>
+
<title>NC.Sub</title>
 
<short_description>
 
<short_description>
 
Subtraction of two polynomials in a non-commutative polynomial ring.
 
Subtraction of two polynomials in a non-commutative polynomial ring.
Line 10: Line 10:
 
<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>NC.SetFp</ref>, <ref>NC.SetX</ref> and <ref>NC.SetOrdering</ref>, respectively, before calling the function. The default coefficient field is <tt>Q</tt>. The default ordering is length-lexicographic ordering (<quotes>LLEX</quotes>). For more information, please check the relevant functions.
+
Please set non-commutative polynomial ring (via the command <ref>Use</ref>) and word ordering (via the function <ref>NC.SetOrdering</ref>) before calling this function. The default word ordering is the length-lexicographic ordering (<quotes>LLEX</quotes>). For more information, please check the relevant commands and functions.
 
<itemize>
 
<itemize>
<item>@param <em>F1, F2:</em> two polynomials in <tt>K&lt;X&gt;</tt>, which are left and right operands of subtraction respectively. Each polynomial is represented as a LIST of monomials, which are pairs 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>F1, F2:</em> two non-commutative polynomials, which are left and right operands of subtraction respectively. Each polynomial is represented as a LIST of LISTs, and each element in every inner LIST involves only one indeterminate or none (a constant). For example, the polynomial <tt>f=2x[2]y[1]x[2]^2-9y[2]x[1]^2x[2]^3+5</tt> is represented as [[2x[1],y[1],x[2]^2], [-9y[2],x[1]^2,x[2]^3], [5]]. The zero polynomial <tt>0</tt> is represented as the empty LIST [].</item>
 
<item>@return: a LIST which represents the polynomial equal to <tt>F1-F2</tt>.</item>
 
<item>@return: a LIST which represents the polynomial equal to <tt>F1-F2</tt>.</item>
 
</itemize>
 
</itemize>
Line 43: Line 43:
 
</description>
 
</description>
 
<seealso>
 
<seealso>
<see>Introduction to CoCoAServer</see></seealso>
+
<see>Use</see>
 +
<see>NC.SetOrdering</see>
 +
<see>Introduction to CoCoAServer</see>
 +
</seealso>
 
<types>
 
<types>
 
<type>apcocoaserver</type>
 
<type>apcocoaserver</type>
Line 49: Line 52:
 
<type>non_commutative</type>
 
<type>non_commutative</type>
 
</types>
 
</types>
<key>ncpoly.Subtract</key>
+
<key>ncpoly.Sub</key>
<key>NC.Subtract</key>
+
<key>NC.Sub</key>
<key>Subtract</key>
+
<key>Sub</key>
 
<wiki-category>Package_ncpoly</wiki-category>
 
<wiki-category>Package_ncpoly</wiki-category>
 
</command>
 
</command>

Revision as of 17:46, 25 April 2013

NC.Sub

Subtraction of two polynomials in a non-commutative polynomial ring.

Syntax

NC.Sub(F1:LIST, F2:LIST):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 non-commutative polynomial ring (via the command Use) and word ordering (via the function NC.SetOrdering) before calling this function. The default word ordering is the length-lexicographic ordering ("LLEX"). For more information, please check the relevant commands and functions.

  • @param F1, F2: two non-commutative polynomials, which are left and right operands of subtraction respectively. Each polynomial is represented as a LIST of LISTs, and each element in every inner LIST involves only one indeterminate or none (a constant). For example, the polynomial f=2x[2]y[1]x[2]^2-9y[2]x[1]^2x[2]^3+5 is represented as [[2x[1],y[1],x[2]^2], [-9y[2],x[1]^2,x[2]^3], [5]]. The zero polynomial 0 is represented as the empty LIST [].

  • @return: a LIST which represents the polynomial equal to F1-F2.

Example

NC.SetX(<quotes>abc</quotes>); 				
NC.SetOrdering(<quotes>ELIM</quotes>); 				
F1 := [[1,<quotes>a</quotes>],[1,<quotes></quotes>]]; 				
F2 := [[0,<quotes>b</quotes>],[1,<quotes>ba</quotes>]];	
NC.Subtract(F1,F2); -- over Q (default field)
[[-1, <quotes>ba</quotes>], [1, <quotes>a</quotes>], [1, <quotes></quotes>]]
-------------------------------
NC.RingEnv();
Coefficient ring : Q
Alphabet : abc
Ordering : ELIM
-------------------------------
NC.SetFp(); -- set default Fp = F2
NC.RingEnv();
Coefficient ring : Fp = Z/(2)
Alphabet : abc
Ordering : ELIM
-------------------------------
NC.Subtract(F1,F2); -- over F2
[[1, <quotes>ba</quotes>], [1, <quotes>a</quotes>], [1, <quotes></quotes>]]
-------------------------------
NC.Subtract(F1,F1);
[ ]
-------------------------------

See also

Use

NC.SetOrdering

Introduction to CoCoAServer