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Overview of GAP 4.10.2 release #3503

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116 changes: 116 additions & 0 deletions doc/changes/changes-4.10.xml
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Expand Up @@ -804,4 +804,120 @@ includes a database of classical and skew braces of small orders.

</Section>

<Section Label="GAP4.10.2">
<Heading>&GAP; 4.10.2 (June 2019)</Heading>

<Subsection Label="Changes in the core GAP system introduced in GAP 4.10.2">
<Heading>Changes in the core &GAP; system introduced in &GAP; 4.10.21</Heading>

Improvements in the experimental way to allow 3rd party code to link &GAP; as a library:
<List>
<Item>
Add <C>GAP_AssignGlobalVariable</C> and <C>GAP_IsNameOfWritableGlobalVariable</C>
to the <Package>libGAP</Package> API
(<URL><LinkText>&Hash;3438</LinkText><Link>https://github.com/gap-system/gap/pull/3438</Link></URL>).
</Item>
</List>

Fixes in the experimental support for using the <Package>Julia</Package>
garbage collector:
<List>
<Item>
Fix of a problem where the Julia GC during a partial sweep frees some,
but not all objects of an unreachable data structure, and also may
erroneously try to mark the deallocated objects
(<URL><LinkText>&Hash;3412</LinkText><Link>https://github.com/gap-system/gap/pull/3412</Link></URL>).
</Item>
<Item>
Fix stack scanning for the Julia GC when GAP is used as a library
(<URL><LinkText>&Hash;3432</LinkText><Link>https://github.com/gap-system/gap/pull/3432</Link></URL>).
</Item>
</List>

Fixed bugs that could lead to crashes:
<List>
<Item>
Fix a bug in <Ref BookName="ref" Oper="TransformationListList" />
which could cause a crash
(<URL><LinkText>&Hash;3463</LinkText><Link>https://github.com/gap-system/gap/pull/3463</Link></URL>).
</Item>
</List>

Fixed bugs that could lead to incorrect results:
<List>
<Item>
Fix a bug in <Ref BookName="ref" Attr="ClassPositionsOfLowerCentralSeries" />. [Reported by Frieder Ladisch]
(<URL><LinkText>&Hash;3321</LinkText><Link>https://github.com/gap-system/gap/pull/3321</Link></URL>).
</Item>
<Item>
Fix a dangerous bug in the comparison of large negative integers,
introduced in GAP 4.10.1: if <C>x</C> and <C>y</C> were equal,
but not identical, large negative numbers then <C>x &lt; y</C>
returned <K>true</K> instead of <K>false</K>.
(<URL><LinkText>&Hash;3478</LinkText><Link>https://github.com/gap-system/gap/pull/3478</Link></URL>).
</Item>
</List>

Fixed bugs that could lead to break loops:
<List>
<Item>
If the group has been obtained as subgroup from a Fitting free/solvable radical computation,
the data is inherited and might not guarantee that the factor group really is Fitting free.
Added a check and an assertion to catch this situation
(<URL><LinkText>&Hash;3154</LinkText><Link>https://github.com/gap-system/gap/pull/3154</Link></URL>).
</Item>
<Item>
Fix declaration of sparse action homomorphisms
(<URL><LinkText>&Hash;3281</LinkText><Link>https://github.com/gap-system/gap/pull/3281</Link></URL>).
</Item>
<Item>
<C>LatticeViaRadical</C> called <Ref BookName="ref" Func="ClosureSubgroupNC" />
assuming that the parent contained all generators. It now calls
<Ref BookName="ref" Oper="ClosureSubgroup" /> instead, since this can
not be always guaranteed (this could happen, for example, in perfect
subgroup computation). Also added an assertion to
<Ref BookName="ref" Func="ClosureSubgroupNC" />
to catch this situation in other cases. [Reported by Serge Bouc]
(<URL><LinkText>&Hash;3397</LinkText><Link>https://github.com/gap-system/gap/pull/3397</Link></URL>).
</Item>
<Item>
Fix a "method not found" error in
<Ref BookName="ref" Func="SubdirectProduct" />
(<URL><LinkText>&Hash;3485</LinkText><Link>https://github.com/gap-system/gap/pull/3485</Link></URL>).
</Item>
</List>

Other fixed bugs:
<List>
<Item>
Fix corner case in modified Todd-Coxeter algorithm when relator is trivial
(<URL><LinkText>&Hash;3311</LinkText><Link>https://github.com/gap-system/gap/pull/3311</Link></URL>).
</Item>
</List>

</Subsection>

<Subsection Label="New and updated packages since GAP 4.10.1">
<Heading>New and updated packages since &GAP; 4.10.1</Heading>

&GAP; 4.10.1 distribution contains 145 packages, including updated
versions of 55 packages from &GAP; 4.10.1 distribution,
<P/>

A new package <Package>MonoidalCategories</Package> by Mohamed Barakat,
Sebastian Gutsche and Sebastian Posur have been added to the distribution.
It is based on the <Package>CAP</Package> package and implements monoidal
structures for <Package>CAP</Package>.
<P/>

Unfortunately we had to withdraw the <Package>QaoS</Package>
package from distribution of GAP, as the servers it crucially
relies on for its functionality have been permanently retired
some time ago and are not coming back
(see <URL>https://github.com/gap-packages/qaos/issues/13</URL> for details).

</Subsection>

</Section>

</Chapter>