Dear GAP Forum,

This is to announce the release of GAP 4.7.7, which could be downloaded from

  http://www.gap-system.org/Releases/

This release includes not only improvements and fixed bugs, but also two new 
GAP packages:

- json package by Christopher Jefferson, providing a mapping between the 
JSON markup language and GAP;

- SglPPow package by Bettina Eick and Michael Vaughan-Lee, providing the 
database of p-groups of order p^7 for p > 11, and of order 3^8.

Also, Windows users may now use the standard installer 

  http://www.gap-system.org/pub/gap/gap47/exe/gap4r7p7_2015_02_13-15_29.exe

which since GAP 4.7.6 became an official format for the GAP distribution 
for Windows. Alternative installers for Linux and OS X (BOB and GAP Rsync) 
will hopefully be updated later.

The overview of changes in GAP 4.7.7 versus GAP 4.7.6 is given below.

New features:

- Introduced some arithmetic operations for infinity and negative infinity.

- Introduced new property 'IsGeneratorsOfSemigroup' which reflects whether 
the list or collection generates a semigroup.

Fixed bugs which could lead to incorrect results:

- Fixed a bug in 'Union' (actually, in the internal library function 
'JoinRanges') caused by downward running ranges. [Reported by Matt Fayers]

- Fixed a bug where recursive records might be printed with the wrong 
component name, coming from component names being ordered differently 
in two different pieces of code. [Reported by Thomas Breuer]

- The usage of abs in src/gmpints.c was replaced by 'AbsInt'. The former 
is defined to operate on 32-bit integers even if GAP is compiled in 
64-bit mode. That lead to truncating GAP integers and caused a crash in 
'RemInt', reported by Willem De Graaf and Heiko Dietrich. Using 'AbsInt' 
fixes the crash, and ensures the correct behaviour on 32-bit and 64-bit 
builds.

Fixed bugs that could lead to break loops:

- A problem with 'ProbabilityShapes' not setting frequencies list for 
small degrees. [Reported by Daniel Błażewicz and independently by Mathieu 
Gagne]

- An error when generating a free monoid of rank infinity. [Reported by 
Nick Loughlin]

- Several bugs with the code for Rees matrix semigroups not handling 
trivial cases properly.

- A bug in 'IsomorphismTypeInfoFiniteSimpleGroup' affecting one particular 
group due to a misformatting in a routine that translates between the 
Chevalley type and the name used in the table (in this case, "T" was 
used instead of ["T"]). [Reported by Petr Savicky]

Other fixed bugs:

- The 'Basis' method for full homomorphism spaces of linear mappings did 
not set basis vectors which could be obtained by 'GeneratorsOfLeftModule'.

- A problem with 'GaloisType' entering an infinite loop in the routine for 
approximating a root. [Reported by Daniel Błażewicz]

- Fixed the crash when GAP is called when the environment variables HOME 
or PATH are unset. [Reported by Bill Allombert]

In addition to the two new packages mentioned above, GAP 4.7.7 distribution 
includes updates of 17 other GAP packages:

Package name          | Version     | Date
------------------------------------------------
Circle                | 1.5.3       | 13/02/2015 
CoReLG                | 1.20        | 02/12/2014  
gpd                   | 1.31        | 17/12/2014  
GradedModules         | 2015.01.30  | 30/01/2015  
HomalgToCAS           | 2015.02.03  | 03/02/2015 
idrel                 | 2.21        | 10/12/2014 
json                  | 0.8.2       | 08/02/2015 
kan                   | 1.11        | 10/12/2014 
LiePRing              | 1.8         | 08/11/2013   
LocalizeRingForHomalg | 2014.11.20  | 20/11/2014 
MatricesForHomalg     | 2015.02.03  | 03/02/2015 
Modules               | 2015.02.10  | 10/02/2015 
RingsForHomalg        | 2015.02.10  | 10/02/2015 
Semigroups            | 2.2         | 20/01/2015 
SglPPow               | 0.9         | 21/11/2014  
TomLib                | 1.2.5       | 21/11/2014  
ToolsForHomalg        | 2014.12.08  | 08/12/2014  
Wedderga              | 4.7.2       | 24/11/2014   
XMod                  | 2.31        | 17/12/2014  
================================================


We encourage all users to upgrade to GAP 4.7.7. If you need any 
help or would like to report any problems, please do not hesitate 
to contact us at supp...@gap-system.org.


Wishing you fun and success using GAP,

The GAP Group


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