===========================================================================
 This file describes changes in the GAP package 'polycyclic'.
 
 This file was added after the 2.8.1 release. Any information pertaining
 older polycyclic versions may not be complete accurate, as it was
 re-created from old records. If you notice anything amiss, please let
 us know.
===========================================================================

2.11 (2013-03-07)
	o Added a fast SylowSubgroup method (via IsomorphismPcGroup)
    o Add FreeAbelianGroup constructor method (feature will only be available
      in a future GAP release)
    o Replaced some internal code dealing with integer matrices with calls
      to equivalent GAP functions; for some things (e.g. inverting a matrix),
      this can be a lot faster
    o Fixed regressions in 2-cohomology code (introduced in 2.9), which caused
      TwoCoboundariesCR and TwoCohomologyCR to produce errors or wrong results
    o Fixed infinite recursion in LowerCentralSeriesOfGroup for non-nilpotent
      pcp groups (thanks to Andreas Distler for noticing and fixing this)
    o Removed support for GAP 4.4, now GAP 4.5 or newer is required
    o Removed some obsolete code
    o Removed or hid multiple undocumented internal functions (such as AsMat,
      IntMat, OnVectorspace, VERIFY, ...) to reduce the pollution of the
      global namespace
	o Various minor tweaks

2.10.1 (2012-06-01)
	o Fixed generic IsFreeAbelian method to only apply to finitely
	  generated groups
	o Removed "name strings" from two InstallImmediateMethod calls;
	  this should have no effect on any user, and is done to silence
	  some pedantic warnings in the GAP test suite

2.10 (2012-05-31)
	o Added methods for GAP's Epicentre and EpimorphismSchurCover attribute
	o Added group constructors that allow construction extraspecial groups
	  as well as alternating and symmetric groups of degree <= 4 as pcp groups
	o Changed SchurExtension and SchurExtensionEpimorphism into attributes
	o Changed IsomorphismPcpGroup for pcp groups, now returns identity map
	o Changed SchurCovering to be a synonym for GAP's SchurCover attribute
	o Fixed regression in AddFieldCR which caused incorrect errors
	  (e.g. when testing whether a pcp group is torsion free)
	o Fixed some warnings by adding a IsGeneratorsOfMagmaWithInverses
	  method for pcp element collections
	o Fixed several bugs resulting in errors when computing Schur extensions,
	  nonabelian exterior and tensor squares, and so on, but only if the
	  argument was a subgroup of a pcp group
	o Fixed computing Schur extensions, nonabelian exterior and tensor squares
	  etc. of the infinite cyclic group
	o Fixed bug in direct products of pcp groups that could result in
	  wrong embedding and projection maps
	o Fixed error triggered when calling NormalizerOp on two groups
	  that have differing Parent() groups, yet still are subgroups
	  of a common overgroup
	o Removed some dead obsolete code

2.9 (2012-01-12)
	o Updated README
	o Added GPL license text
	o Added this CHANGES file
	o Added Max Horn to authors / maintainer list
	o Removed Werner Nickel from maintainer list
	o Removed compatibility with GAP versions before 4.4
	o Removed redundant IsomorphismPermGroup method
	o Removed redundant IsPcpGHBI group mapping representation
	o Added various group constructors (TrivialGroupCons etc.),
	  so that it is now possible to construct Pcp groups with e.g.
	  TrivialGroup(IsPcpGroup) or DihedralGroup(IsPcpGroup, infinity).
	  Specifically, this works now for cyclic, (elementary) abelian,
	  dihedral, and quaternion groups
	o Added implementations of IndependentGeneratorsOfAbelianGroup and
	  IndependentGeneratorExponents for pcp groups
	o Improved handling of homomorphisms between pcp groups and non-pcp
	  groups
	o Improved validation of input for various functions / methods
	o Improved AbelianPcpGroup to flag the constructed group as abelian
	o Fixed AbelianInvariants to return values that match what the GAP
	  documentation promises the user
	o Fixed a bug that caused TwoCohomologyCR and many related operations
	  to error out if the cohomology record was obtained using
	  CRRecordBySubgroup or CRRecordByPcp
	o Fixed bug comparing homomorphisms between pcp groups by removing
	  the (incorrect) method for this; the default method provided by
	  GAP is now used and returns correct results
	o Fixed ClosureGroup method to not make invalid assumptions about
	  a group's Parent (and thus no longer return incorrect results)
	o Fixed bug causing general mappings from/to pcp groups to be
	  always marked as total, even if they were in fact not
	o Added IsNilpotentByFinite methods for finite and nilpotent groups
	o Added immediate IsTorsionFree method for finite groups
	o Added IsFreeAbelian method for arbitrary groups, turned it into
	  a property
	o Converted documentation to GAPDoc format
	o Replaced internal function DepthOfVec by GAP's PositionNonZero
	o Added (trivial) IsomorphismPcpGroup method for pcp groups
	o Added a String method for pcp elements

2.8.1 (2011-05-24)
	o Use Calcreps2 instead of calcreps2 for compatibility with GAP 4.5
	o Updated homepage URLs

2.8 (2011-01-26)
	o Improved and corrected parts of the manual
	o Removed IsomorphismPcpGroup method for fpgroups, and instead
	  provide and document it as a regular function under the name
	  IsomorphismPcpGroupFromFpGroupWithPcPres
	o Use "-u" option when creating the HTML manual to produce unicode
	  output
	o Removed SchurMultiplicator method and instead install a method
	  for AbelianInvariantsMultiplier

2.7: Never released

2.6 (2009-02-18)
	o Disabled (and removed any mention from the documentation) some code
	  dealing with Schur towers of p-groups of fixed coclass.
	o Fixed email address of Bettina Eick

2.5 (2008-11-25)
	o Added SchurCovers
	o Added dependency on autpgrp package
	o Added GroupHomomorphismByImagesNC implementation for when the source
	  is a Pcp group, but the range is possibly not.
	o Compute size of newly constructed group in PcpGroupByCollectorNC
	o Various other fixes and improvements

2.4 (2008-11-12)
    o Fixed a bug in DirectProduct for PcpGroups

2.3 (2008-11-09)
	o Removed compatibility with GAP versions before 4.3
	o Added WhiteheadQuadraticFunctor
	o Added IsPolycyclicPresentation
	o Added IsomorphismPermGroup
	o Renamed DepthVector -> DepthOfVec
	o Renamed PrintFullPresentation -> PrintPcpPresentation
	o Renamed Tail -> TailOfElm
	o Replaced many uses of BindGlobal by InstallGlobalFunction
	o Improved group homomorphism code
	o Implemented Embedding and Projection for DirectProduct
	o Implemented Embedding for WreathProduct
	o Extended AbelianPcpGroup to accept types of arguments (undocumented)
	o Various other fixes and improvements

2.2 (2007-06-22)
	o Added support for non-abelian tensor and exterior squares
	o TODO:  Schur extensions code was also touched?
	o Various other fixes and improvements

2.1 (2006-11-07)
	o Declare in PackageInfo.g that nq is a suggested (but not required)
	  external package, and try harder to work when nq is missing.
	o Rewrote SchurExtension
	o Changed IsomorphismPcGroup to first convert the group to a refined
	  pcp group; also, the resulting homomorphism is now marked as being
	  a group homomorphism.
	o Several existing functions now are "properly" installed via
	  InstallMethod or InstallGlobalFunction
	o Various other fixes and improvements

2.0 (2006-10-23)

1.1 (2003-10-15)

1.0 (???)
