ApCoCoA:Cyclic groups

From CoCoAWiki
Jump to: navigation, search

Description

Every cyclic group is generated by a single element a. If n is finite the group is isomorphic to Z/nZ, otherwise it can be interpreted as Z with the addition of integers as the group operation. For every cyclic group there only exists one subgroup containing a, the group itself.

C(n) = <a | a^{n} = 1>

Reference

Joseph A. Gallian, Contemporary Abstract Algebra (4th ed.), Boston: Houghton Mifflin, Chapter 4, 1998.

Computation

 /*Use the ApCoCoA package ncpoly.*/
 
 // Number of cyclic group
 MEMORY.N:=5;
 
 Use ZZ/(2)[a];
 NC.SetOrdering("LLEX");
 
 Define CreateRelationsCyclic()
   Relations:=[];
   // Add relation a^n = 1
   Append(Relations,[[a^MEMORY.N],[1]]);
   Return Relations;
 EndDefine;
 
 Relations:=CreateRelationsCyclic();
 Relations;
 
 // Compute a Groebner Basis.
 Gb:=NC.GB(Relations);
 Gb;
 // RESULT for MEMORY.N = 5 :: [[[a^5], [1]]]

Example in Symbolic Data Format

 <FREEALGEBRA createdAt="2014-03-02" createdBy="strohmeier">
 	<vars>a</vars>
 	<basis>
 	<ncpoly>a^5-1</ncpoly>
 	</basis>
 	<Comment>Cyclic_group_5</Comment>
 </FREEALGEBRA>