CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutSign UpSign In

Real-time collaboration for Jupyter Notebooks, Linux Terminals, LaTeX, VS Code, R IDE, and more,
all in one place.

| Download

GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it

Views: 418346
Tweet
Share
Share

CHANGES to the 'XMod' package

Problems and ToDos:

  • (30/10/17) there is no IsCrossedSquare method - and IsPreCrossedSquare makes no checks on the crossed pairing map

  • (13/10/17) need more examples in 2.1, e.g. DirectProductOp (+Proj,Embed)

  • (07/08/17) coprod.tst and gpnobjmap.tst need to work with new groupoids

  • (22/07/17) X4 (etc) is a HigherDimensionalDomain but not a HigherDimensionalGroup - discrepancy to be sorted out!

  • (14/06/17) Need String, View, Print for 3d- and nd-groups

  • (28/04/17) implement inclusion of the kernel of an xmod-morphism as xsq

  • (25/04/17) file examples/gpd2obj.g needs more material

  • (19/08/16) error report from Tedar Tegstrom: he discovered that InducedXMod(X0,iota) fails when Boundary(X0) not mono.

  • (16/06/16) document more utility functions or move them to Utils

  • (11/11/15) resolve the problem of the best 'sgQ1' to use in Isoclinism, and more generally, check whether using SmallGeneratingSet elsewhere allows for spurious results in the isoclinism functions

  • (09/11/15) resolve whether XModCentre = CentreXMod

  • (15/10/15) need a function CrossedSquareByCentralExtension

  • (24/09/15) keep or dispose of the dom2d3d functions?

  • (03/09/15) XModCentre etc. fail with pc-groups

  • (22/06/12) need to fix construction of endomorphism classes so that they can be printed/displayed.

  • (15/02/12) failed to construct induced xmod from X = (SL25 -> SL25.C2) and the inclusion SL25.C2 -> GL25 using the matrix groups (construction worked OK with isomorphic perm groups).

2.63 -> 2.64 (30/11/2017)

  • (29/11/17) fixed tests to work with both 4r8 and dev in 3 options

  • (23/11/17) removed attribute AutoGroup (=Range(XModAction)) for xmods

  • (22/11/17) added operations SinglePiecePreXModWithObjects(NC)

  • (16/11/17) added Root2dGroup for prexmods with objects

  • (17/10/17) ImageElmXModAction now working for xmods of groupoids

  • (04/10/17) added operation ImageElmXModAction

  • (01/10/17) renamed test files and made them independent

  • (27/09/17) added tst/testextra.g, tst/allxmods.xtst, tst/cat1mor.xtst

2.61 -> 2.63 (26/09/2017)

  • (26/09/17) added a number of Types and modified Objectify statements removed Up2DimensionalMappingObj

  • (24/08/17) changed the name of Murat's university

  • (09/08/17) in order to keep XModAlg-1.12 working, added synonyms Is2dDomain for Is2DimensionalDomain, PreCat1ByTailHeadEmbedding for PreCat1Obj, PreCat1ByEndomorphisms for PreCat1GroupByEndomorphisms PreCat1ByPreXMod for PreCat1GroupOfPreXMod IsGeneral2dMapping for IsGeneral2DimensionalMapping and Kernel2dMapping for Kernel2DimensionalMapping

2.59 -> 2.61 (07/08/2017)

  • (07/08/17) Gpd changed to groupoids in list of required packages

  • (07/08/17) testall.g now calls TestDirectory; test files renamed

  • (07/08/17) temporarily renamed 08-gpd2obj.tst and 11-gpnobjmap.tst so that they do not get tested by TestDirectory("tst")

  • (21/07/17) replaced PreXModIsomorphismByIsomorphisms by the more general IsomorphismByIsomorphisms; then functions such as IsomorphismPerm2DimensionalGroup rewritten to use it.

  • (20/07/17) added IsomorphismByIsomorphisms for pre1-cat-groups

  • (20/07/17) Removed duplication in 'Of' and 'By' operations

  • (17/07/17) new functions added by Alper for crossed square <-> cat2-group: ConjugationActionForCrossedSquare; ElementsRelationsForSemidirectProduct

  • (14/06/17) added methods for String, ViewString, PrintString

  • (09/05/17) dom2d3d.g{d,i} renamed dom2dnd.g{d,i} hdim-morphisms now expect [ src, rng, list of maps ] PreCatn(Mapping)Dimension now HigherDimension added attribute VertexGroups for HigherDimensionalGroups

  • (08/05/17) Removed lots of 3Dim stuff since HigherDim stuff is better

  • (05/05/17) AllCat1Groups* -> AllCat1DataGroups*

  • (04/05/17) Alper add catn-morphism functions in gpnmor.g{d,i}

  • (29/04/17) added lines to makedoc.g to allow for xymatrix commands

  • (24/04/17) 2d

  • (22/04/17) Alper added lib/gpnobj.gd, lib/gpnobj.gi, tst/gpnobjmap.tst

  • (10/04/17) Alper added a number of functions for cat2-groups and morphisms Replaced XPairing with CrossedPairing

  • (04/04/17) added CoproductInfo for coproducts FactorXMod now FactorPreXMod (ditto NaturalMorphisms)

  • (27/03/17) added Is2dGroupMorphismData and modified construction functions Method for IsNormal now applies to precrossed modules added PeifferSub2dGroup

  • (24/03/17) added operation DiagonalCat1 and example S3xS3 => S3

  • (22/03/17) added operation CoproductXMod and files coprod.g, coprod.tst

2.58 -> 2.59 (21/03/2017)

  • (21/03/17) added property IsEndomorphismPreCat1 modified IsomorphismPerm2dGroup for PreCat1 objects

  • (14/11/16) "first author" -> "second author" in manual.xml (issue #4)

2.56 -> 2.58 (02/11/2016)

  • (18/10/16) now using bibliography file bib.xml of type bibxmlext.dtd

  • (13/10/16) changed package releases to https://gap-packages.github.io/xmod

  • (24/03/16) added files hap.gd, hap.gi

  • (16/03/16) edited utils.tst to remove functions transferred to Utils

2.51 -> 2.56 (08/03/2016)

  • (23/02/16) remove functions from util.g{d/i} now in Utils; require Utils

  • (18/02/16) removed date/version info from file headers

  • (16/02/16) require Gpd >= 1.42;

2.45 -> 2.51 (09/02/2016)

  • (08/02/16) necessary changes to test files to fix new output errors

2.44 -> 2.45 (29/12/2015)

  • (29/12/15) fixed changes in output from \*.tst files

2.42 -> 2.44 (13/11/2015)

  • (11/11/15) renamed Rank and MiddleLength and now for p-groups only

  • (10/11/15) changes examples in tests to avoid repeated variable names

  • (09/11/15) XPair -> XPairing, etc.

  • (08/11/15) IsomorphismPermPre(XMod/Cat1) -> IsomorphismPerm2dGroup, etc.

  • (07/11/15) Revised manual, chapter 7, and isoclinic.tst

  • (06/11/15) IsStemGroup & IsStemXMod -> IsStemDomain etc.

  • (04/11/15) RestrictionMappingGroups -> GeneralRestgrictedMapping

  • (01/11/15) makedocrel.g : added MathJax; changed "doc" to XModDoc

  • (20/10/15) moved code from FactorXMod to NaturalMorphiusmByNormalSubXMod corrected formulae in Displacement and DisplacementSubgroup

  • (19/10/15) revised Isoclinism for xmods; IsoAllXMods -> AllXModsUpToIso..

  • (16/10/15) changed all occurrences of XSq to CrossedSquare

  • (15/10/15) fixed Iterator bug in Isoclinism for groups

  • (13/10/15) CentralQuotient now a crossed module or a crossed square added LeftRightMorphism and UpDownMorphism for crossed squares

  • (07/10/15) AllXMods and AllPreXMods now global functions added property IsStemXMod

  • (06/10/15) renamed IsIsomorphicXMod as IsomorphismXMods; fixed the call to IsXMod in PreXModObj

  • (05/10/15) added Centralizer and Normalizer methods for crossed modules

  • (02/10/15) added ExternalSetXMod

  • (01/10/15) added operation Displacement

  • (28/09/15) added AllStemGroupFamilies and Set various Names

  • (26/09/15) added NaturalHomomorphismByNormalSubXMod

  • (24/09/15) added CrossActionSubgroup

  • (23/09/15) removed last occurrences of AllIsomorphisms

  • (22/09/15) added functions for isoclinism of groups

  • (18/09/15) processed a number of properties in the isoclinic files

  • (17/09/15) added example in manual subsection 2.1.4.

  • (15/09/15) methods for InnerMorphism, ActorXMod, CentreXMod, etc. now specified only for permutation crossed modules

  • (24/08/15) major edits to README, including GitHub issues link

2.41 -> 2.42 (24/08/2015)

  • (24/08/15) made version to be moved from Bitbucket to GitHub

  • (20/07/15) fixed bug in IsomorphismPcPreCat1 reported by Charles Melville

2.32 -> 2.41 (05/06/2015)

  • (05/06/15) gpd2obj.gd changed to reflect changes in package Gpd

2.31 -> 2.32 (26/02/2015)

  • (26/02/15) reverted AllInducedXMods(Cat1s) to global functions

  • (03/02/15) added properties IsPreXModDomain and IsPreCat1Domain which are meant to apply to both group and algebra cases

  • (02/02/15) took out all MultiplicativeElementWithTuple's etc. and Multiplicative2dElement's etc.

  • (29/01/15) made copies of dom2d3d,g{d,i} and gp2obj.g{d,i} before embarking on a major rewrite of the category structure: specifically, changing lots of '2dDomain's into '2dGroup's

2.26 -> 2.31 (17/12/2014)

2.22 -> 2.26 (26/11/2013)

  • (26/11/13) minor mod to WhiteheadTransMonoid to fix gp2up.tst output

  • (03/11/13) fixed errors in cat1data.g reported by Van Luyen Le.

  • (15/10/13) fixed error in Cat1MorphismByXModMorphism.

  • (03/10/13) completed work on groups of order [64..70] in cat1data.g

  • (02/10/13) added operation CollectPartsAlreadyDone.

  • (01/10/13) added operation PreCat1IsomorphismByIsomorphisms.

  • (17/08/13) fixed bug in PermCat1Select sent by Van Luyen Le

  • (26/03/13) put groups of order 64 back into cat1data.g

  • (05/02/13) rewrite of testall.g following Alex K's wedderga example

2.19 -> 2.22 (25/01/2013)

  • (25/01/13) Minor change to test file output to avoid problems in tests.

  • (09/01/13) Changed PackageWWWHome, using "gap4" rather than "gap4r5". Unable to fix problems related to changes in lib/ghom.gi, so removed gpd2obj.tst from the set of standard tests: the problem is with changes to GroupGeneralMappingByImages.

  • (26/09/12) Moved functions to the new cat1data.gd, cat1data.gi.

  • (21/09/12) Edited test files to reflect recent changes

  • (12/07/12) Changed the format and rebuilt the data file cat1data.g :- it is now assumed that the SmallGroups library is used. Extended cat1data.g from order 47 to most of order 64. Major revision of AllCat1s, MakeAllCat1s, Cat1Select

  • (04/07/12) Added AllCat1s and IsomorphismPreCat1s (from GAP3 version). Removed batch of functions from util.g{d,i} involving EndomorphismClasses, IdempotentImages, etc. Replaced their use in AllCat1s with calls to GQuotients.

2.18 -> 2.19 (09/06/2012)

  • (08/06/12) Following the replacement of IdentitySubgroup by TrivialSubgroup in Gpd, renamed IdentitySubXMod by TrivialSubXMod, etc. All calls of GroupHomomorphismByImagesTriv returned to GroupHomomorphismByImages (see item dated 30/04/08)

  • (07/06/12) Renamed special Display for lists as PrintListOneItemPerLine following email from Max Horn

2.17 -> 2.18 (23/04/2012)

  • (23/04/12) added autpgrp as a needed package

  • (26/01/12) replaced XModActedUpon by AutomorphismDomain in gp2act.g{d,i}

  • (25/01/12) fixed error in XModByGroupOfAutomorphisms (oneG now oneP)

  • (10/01/12) updated to 2012; corrected URLs in intro.xml

  • (15/12/11) now requires version 1.13 of 'Gpd'

2.15 -> 2.17 (21/09/2011)

  • (20/09/11) new version of makedocrel.g for building the manual added file gpd/examples/readall.g for testing purposes

  • (17/09/11) Shortened the banner.

  • (16/09/11) Renamed subdirectory xmod/gap as xmod/lib

2.14 -> 2.15 (06/09/2011)

  • (04/09/11) Changed BIND_GLOBAL to BindGlobal, since it is safer

  • (16/08/11) changed directory for archive to .../chda/gap4r5/xmod/

2.13 -> 2.14 (30/07/2011)

  • (30/07/11) final adjustments to the test files

  • (29/07/11) major changes to gp3objmap.g{d,i}.

  • (28/07/11) new 16/07/11 files now dom2d3d.gd etc.

  • (27/07/11) ViewObj, PrintObj, Display, Name now methods for 2d-groups.

  • (19/07/11) IsUp2dMapping now a category. InducedXMod( s4, s3b, s3b ) fails due to iso to pc-group, fo forced (for now) an isomorphism to a perm group.

  • (18/07/11) Centre of an xmod no longer works, so brought back XModCentre.

  • (16/07/11) Introduced a range of new categories in files dom2d.gd, dom2d.gi, map2d.gd, map2d.gi. As a result there were many changes in all files.

  • (08/07/11) Changed headers of all files.

  • (06/07/10) Changed XModByGroupOfAutomorphisms(G) in case G is pcgroup

  • (02/07/10) New email address for Murat

  • (30/06/10) Added check for IsPc2dDomain to PreXModObj

  • (30/06/10) InducedXModByCopower now constructs a PcXMod if appropriate

  • (28/06/10) Added methods for IsomorphismPcPreXMod, IsomorphismPcPreCat1

  • (12/03/10) Moved 'XMod' development to IMac at home, and started v.2.14

2.12 -> 2.13 (21/01/2010)

  • (21/01/10) Changed output of AllInducedXMods to list of StructureDesc.

2.11 -> 2.12 (24/11/2008)

  • (19/11/08) GapDoc relegated to "suggested other packages".

2.008 -> 2.11 (13/11/2008)

  • (13/11/08) added GNU General Public License declaration, moved some 'XMod' utilities to gpd/gap/util.g{d,i},

  • (07/11/08) Changed website to: <www.maths.bangor.ac.uk/chda/xmod/> Split the test file into one file per chapter.

  • (30/04/08) Added GroupHomomorphismByImagesTriv to util.gd, util.gi to allow both [removed] and [removed] to be empty: triv -> triv! Fixed bug in XModOfCat1 in assigning names. FixedBug in Boundary for a pre-cat1-group.

  • (31/03/08) Added function GpdBuildManualHTML()

  • (16/03/08) renamed Tail,Head as TailMap,HeadMap (for benefit of 'Gpd')

  • (08/10/07) started this CHANGES file; changed directory permissions from 711 to 755; renamed files: obj2 -> gp2obj, etc, ready for groupoids; added file testall.g in xmod/tst

2.007 -> 2.008 (25/10/2006)

  • Fixed broken links in PackageInfo.g.

2.006 -> 2.007 (20/10/2006)

  • Added basic functions for crossed squares, considered as 3dObjects with crossed pairings, and their morphisms. (Groups with two normal subgroups, and the actor of a crossed module, provide standard examples. Cat2-groups are not yet implemented.)

  • Converted the documentation to the format of the GAPDoc package, and added the function XModBuildManual() to the util.gi file.

  • Improved AutomorphismPermGroup for crossed modules, and introduced a special method for conjugation crossed modules.

  • Substantial revisons made to XModByCentralExtension, NorrieXMod, LueXMod, ActorXMod, and InclusionInducedXModByCopower.

  • Reintroduced the Cat1Select operation.

2.005 -> 2.006 (04/09/2004)

  • Changed morphism functions to return fail when invalid data is supplied, rather than calling Error.

  • Fixed a bug in XModByGroupOfAutomorphisms.

2.004 -> 2.005 (16/04/2004)

  • Moved the example files from tst/test_i.g to examples/example_i.g,

  • converted testmanual.g to a proper test file tst/xmod_manual.tst.

  • Replaced OperationHomomorphism by ActionHomomorphism, a general GAP;4.4 change.

  • Finished replacing RModule by AbelianModule.

  • Renamed UpMapping as Up2dMapping.

  • Added MappingGeneratorsImages and InverseGeneralMapping for a 2dMapping.

  • A significant change was the conversion of the actor crossed module functions from the 3.4.4 version, including AutomorphismPermGroup for a crossed module, WhiteheadXMod, NorrieXMod, LueXMod, ActorXMod, Centre of a crossed module, InnerMorphism and InnerActorXMod.

  • Added SmallerDegreePermPreXMod after discovering, in the library, the very useful SmallerDegreePermutationRepresentation.

2.002 -> 2.004 (14/04/2004)

  • gave a new email address for Murat Alp

  • added the Cat1Select functionality of version 1 to the Cat1 function

2.001 -> 2.002 (January 2004)

  • Version 2.002 was prepared for the 4.4 release at the end of January 2004, and so required a PackageInfo.g file.

Induced Crossed Modules (May 2002)

Converted combinatorial functions -- DistinctRepresentatives, CommonRepresentatives, CommonTransversal and IsCommonTransversal.

Converted Tietze modification functions TzCommutatorPair, TzPartition and FactorsPresentation.

Introduced global functions IsomorphismPermObject, IsomorphismFpObject, and IsomorphismPcObject which call IsomorphismPermGroup etc. when the object is a group. Added functions IsomorphismPermPreXMod, IsomorphismPermPreCat1, etc. to be called when the object is a 2d-object.

Added IsomorphismXModByNormalSubgroup which applies when the boundary of the xmod is injective.

Added PreXModIsomorphismByIsomorphisms (but renamed 21/07/17) (we also need a similar function PreCat1IsomorphismByIsomorphisms) where the data consists of a crossed module, an isomorphism of the source, and an isomorphism of the range.

Changed RModule to AbelianModule.

Version 2.001 for GAP 4 (April 2002)

Generic name UpMapping chosen for derivations and sections (later changed to Up2dMapping).

File names changed to obj2.gd, map2.gi, up2.tex, etc.

Added alternative methods for IsomorphismPermGroup for 2dObjects.

Sorted a problem with fixing the generating set for R when used to define derivations. The (old) code used an fp-group version of R and checks that all the relators map by chi to 1. Unfortunately, IsomorphismFpGroup sometimes permutes the order of the R-generators, with unfortunate effects. The fix used IsomorphismFpGroupByGenerators, which returns the images of the generators specified in the function call. We have also used genR := StrongGeneratorsStabChain( StabChain( rng ) ); throughout to specify the generators of R.

Operation XModMorphism renamed as XModMorphismByHoms, and a new global function XModMorphism introduced (ditto for other 2dMappings).

Now using \chi_1 \star \chi_2 for Whitehead multiplication (on the right), with CompositeDerivation still giving multiplication on the left. This means that the second axiom for derivations and for sections has changed -- see Chapter 4.