  
  [1X1 [33X[0;0YThe Ferret Package[133X[101X
  
  [33X[0;0YThis  chapter  describes  the  [5XGAP[105X  package Ferret. Ferret implements highly
  efficient  implementations  of  a  range of search algorithms on permutation
  groups.  If  you  are  interested  in  if  Ferret  can be applied to another
  problem,  please contact the authors, who will be happy to look into if your
  problem can be solved with Ferret.[133X
  
  
  [1X1.1 [33X[0;0YReplacing Built-in functionality[133X[101X
  
  [33X[0;0YFerret  automatically installs methods which replace GAP's a number of GAP's
  built-in functionality:[133X
  
  [30X    [33X[0;6Y[13XIntersection[113X for a list of permutation groups.[133X
  
  [30X    [33X[0;6Y[13XStabilizer(G,S,Action)[113X for a permutation group G, and the actions:[133X
  
        [30X    [33X[0;12Y[10XOnSets[110X[133X
  
        [30X    [33X[0;12Y[10XOnOnSets[110X[133X
  
        [30X    [33X[0;12Y[10XOnSetsDisjointSets[110X[133X
  
        [30X    [33X[0;12Y[10XOnSetsSets[110X[133X
  
        [30X    [33X[0;12Y[10XOnTuples[110X[133X
  
        [30X    [33X[0;12Y[10XOnPairs[110X[133X
  
        [30X    [33X[0;12Y[10XOnDirectedGraph[110X[133X
  
  [30X    [33X[0;6Y[13XStabilizer(G, S)[113X for a permutation group G and a:[133X
  
        [30X    [33X[0;12Ypermutation[133X
  
        [30X    [33X[0;12Ytransformation[133X
  
        [30X    [33X[0;12Ypartial permutation[133X
  
  [33X[0;0YIf you would like to disable this functionality, you can use [14X1.1-1[114X.[133X
  
  [1X1.1-1 EnableFerretOverloads[101X
  
  [33X[1;0Y[29X[2XEnableFerretOverloads[102X( [[3Xactive[103X] ) [32X function[133X
  
  [33X[0;0Yif   [3Xactive[103X  (a  bool)  is  true,  then  enable  Ferret  specialisations  of
  Intersection and Stabilizer. Call with [3Xactive[103X false to disable.[133X
  
  [1X1.1-2 FerretOverloadsEnabled[101X
  
  [33X[1;0Y[29X[2XFerretOverloadsEnabled[102X(  ) [32X function[133X
  
  [33X[0;0YReturn   if  Ferret  specialisations  of  Intersection  and  Stabilizer  are
  currently enabled.[133X
  
  
  [1X1.2 [33X[0;0YUsing 'Solve' to solve problems directly[133X[101X
  
  [33X[0;0YThe main method of using Ferret's functionality is the [2XSolve[102X ([14X2.1-3[114X) method.
  This  method intersects a list of permutation groups. The unusual feature is
  that  these permutation groups can be represented in a variety of ways. They
  can  be  usual GAP permutation groups given as a list of generators, or they
  can  be the group which is the stabilizer of combinatorial object under some
  action.  Larger  problems  are then composed from these pieces. For example,
  the  stabilizer  of  a  set  S  under  a  group  G  can  be expressed as the
  intersection  of  the  group which stabilizes the set S and the group G. For
  this problem, there would be no point using [2XSolve[102X ([14X2.1-3[114X), as GAP's built in
  'Stabilizer'  function  provides the same functionality. However, with [2XSolve[102X
  ([14X2.1-3[114X)  we can intersect any number of groups at the same time, for example
  finding  the  intersection  of two groups G and H, the stabilizer of a set S
  and the stabilizer of a set of sets T, with the following code:[133X
  
  [4X[32X  Example  [32X[104X
    [4X[25Xgap>[125X [27XSolve([ConInGroup(G), ConInGroup(H), [127X[104X
    [4X[25X>[125X [27XConStabilize(S, OnSets), ConStabilize(T, OnSetSets)])[127X[104X
  [4X[32X[104X
  
  [33X[0;0YThe currently allowed arguments to [2XSolve[102X ([14X2.1-3[114X) are:[133X
  
  [30X    [33X[0;6Y[2XConInGroup[102X ([14X2.1-2[114X), which represents a Permutation Group in GAP[133X
  
  [30X    [33X[0;6Y[2XConStabilize[102X ([14X2.1-1[114X), which takes an object and an action.[133X
  
