Package sagbi/SB.IsInSubalgebra: Difference between revisions

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{{Version|2|[[ApCoCoA-1:SB.IsSubalgebra]]}}
{{Version|2|[[ApCoCoA-1:SB.IsInSubalgebra]]}}
 
<command>
<command>
   <title>SB.IsInSubalgebra</title>
   <title>SB.IsInSubalgebra</title>
   <short_description>Tests whether a polynomial is in a subalgebra.</short_description>
   <short_description>Tests whether a polynomial is in a subalgebra.</short_description>
    
    
<syntax>
  <syntax>SB.IsInSubalgebra(f:POLY, G:LIST of POLY):BOOL</syntax>
SB.IsInSubalgebra(f:POLY, G:LIST of POLY):BOOL
</syntax>
   <description>
   <description>
This function takes a polynomials <tt>f</tt> and a list of polynomials <tt>G</tt> and checks whether <tt>F</tt> is in the algebra generated by the polynomials in <tt>G</tt>.
This function takes a polynomials <tt>f</tt> and a list of polynomials <tt>G</tt> and checks whether <tt>F</tt> is in the algebra generated by the polynomials in <tt>G</tt>.
<itemize>
    <itemize>
  <item>@param <em>f</em> A polynomial.</item>
      <item>@param <tt>f</tt> A polynomial.</item>
  <item>@param <em>G</em> A list of polynomials which generate a subalgebra.</item>
      <item>@param <tt>G</tt> A list of polynomials which generate a subalgebra.</item>
  <item>@return <tt>true</tt> if <tt>f</tt> is in the subalgebra generated by <tt>G</tt>, <tt>false</tt> elsewise.</item>
      <item>@return <tt>true</tt> if <tt>f</tt> is in the subalgebra generated by <tt>G</tt>, <tt>false</tt> elsewise.</item>
</itemize>
    </itemize>


<example>
    <example>
Use QQ[x[1..2]];
Use QQ[x[1..2]];
G := [x[1]-x[2], x[1]*x[2]-x[2]^2, x[1]*x[2]^2];
G := [x[1]-x[2], x[1]*x[2]-x[2]^2, x[1]*x[2]^2];
SB.IsInSubalgebra(x[1]*x[2]^4-x[2]^5, G);
SB.IsInSubalgebra(x[1]*x[2]^4-x[2]^5, G);
-----------------------------------------------------------------------------
-- true</example>
true
</example>


<example>
    <example>
Use QQ[y[1..3]];
Use QQ[y[1..3]];
G := [y[1]^2-y[3]^2, y[1]*y[2]+y[3]^2, y[2]^2-2*y[3]^2];
G := [y[1]^2-y[3]^2, y[1]*y[2]+y[3]^2, y[2]^2-2*y[3]^2];
SB.IsInSubalgebra(y[3]^4, G);
SB.IsInSubalgebra(y[3]^4, G);
-----------------------------------------------------------------------------
-- false</example>
false
</example>
   </description>
   </description>
  <seealso>
    <see>Package sagbi/SB.IsInSubalgebra_SAGBI</see>
    <see>Package sagbi/SB.IsInSA</see>
    <see>Package sagbi/SB.IsInSA_SAGBI</see>
    <see>Package sagbi/SB.IsInToricRing</see>
  </seealso>
   <types>
   <types>
     <type>sagbi</type>
     <type>sagbi</type>
     <type>poly</type>
     <type>poly</type>
   </types>
   </types>
   <key>sagbi</key>
 
   <key>sb.sagbi</key>
   <key>IsInSubalgebra</key>
   <key>sagbi.sagbi</key>
   <key>SB.IsInSubalgebra</key>
   <wiki-category>ApCoCoA-2.0/Package_sagbi</wiki-category>
   <key>apcocoa/sagbi.IsInSubalgebra</key>
   <wiki-category>Package_sagbi</wiki-category>
</command>
</command>

Latest revision as of 12:55, 26 October 2020

This article is about a function from ApCoCoA-2. If you are looking for the ApCoCoA-1 version of it, see ApCoCoA-1:SB.IsInSubalgebra.

SB.IsInSubalgebra

Tests whether a polynomial is in a subalgebra.

Syntax

SB.IsInSubalgebra(f:POLY, G:LIST of POLY):BOOL

Description

This function takes a polynomials f and a list of polynomials G and checks whether F is in the algebra generated by the polynomials in G.

  • @param f A polynomial.

  • @param G A list of polynomials which generate a subalgebra.

  • @return true if f is in the subalgebra generated by G, false elsewise.

Example

Use QQ[x[1..2]];
G := [x[1]-x[2], x[1]*x[2]-x[2]^2, x[1]*x[2]^2];
SB.IsInSubalgebra(x[1]*x[2]^4-x[2]^5, G);
-- true

Example

Use QQ[y[1..3]];
G := [y[1]^2-y[3]^2, y[1]*y[2]+y[3]^2, y[2]^2-2*y[3]^2];
SB.IsInSubalgebra(y[3]^4, G);
-- false

See also

Package sagbi/SB.IsInSubalgebra_SAGBI

Package sagbi/SB.IsInSA

Package sagbi/SB.IsInSA_SAGBI

Package sagbi/SB.IsInToricRing