[GAP] - GAP – Groups, Algorithms, and Programming, Version 4.16dev, + GAP – Groups, Algorithms, and Programming, Version 4.17dev, The GAP Group (this year), https://www.gap-system.org.
BibXML: --and before theEntering break read-eval-print loop ...
line is produced -by the functionEntering break read-eval-print loop ...
+is produced by the functionyou can enter 'quit;' to ...
⪆ 3 compatibility modeis provided -(see ), -its use will disable some of the new features of ⪆ 4. -Also it certainly can only try to provide partial compatibility. - -For a detailed explanation of the new features and concepts of ⪆ 4, -see the manual
Programming in GAP. - - - -
redirectthe text -
functions areBy
no check. -When fun2 is called then it checks whether its arguments are valid, -and if so then it calls fun1. -The functions
immutableobjects. Such objects cannot be -changed, attempting to do so issues an error. Typically attribute -values are immutable, and also the results of those binary arithmetic -operations where both arguments are immutable, -see Section . -For example,
bypassing the dispatcherby -calling for example
parent(instead of
supergroup) -was chosen to indicate that the parent of an object was more than just -useful information. -In fact the main reason for the introduction of parents was to provide -a common roof for example for all groups of polycyclic words that -belonged to the same PC-presentation, or for all subgroups of a finitely -presented group (see ). -A subgroup was never a parent group, and it was possible to create -subgroups only of parent groups. - -In ⪆ 4 this common roof is provided already by the concept of -
official-workaround to set some components of the mapping record was quite -unwieldy. - -In ⪆ 4,
official wayto construct this natural homomorphism -was to create first the factor structure
operation -homomorphisms, have been replaced (just a name change) by
words in abstract generatorsof -the underlying free groups were (mis)used. This caused problems -whenever calculations with elements were involved, the most obvious -ones being wrong results of element comparisons. Also functions -that should in principle work for any group were not applicable to -finitely presented groups. In effect, a finitely presented group had -to be treated in a special way in ⪆ 3. - -⪆ 4 distinguishes free groups and their elements from finitely -presented groups and their elements. Comparing two elements of a -finitely presented group will yield either the correct result or no -result at all. - -Note that in ⪆ 4, the arithmetic and comparison operations for -group elements do not depend on a context provided by a group that -contains the elements. In particular, in ⪆ 4 it is not -meaningful to call
componentsof domains; - besides components that have no meaning for the rest of the ⪆ 4 - library, such as
oldobject and an -operations record, where the latter was a record containing the -functions applicable to the new object. After the library file -
Programming in ⪆mentioned above.) - -The next step is to write a function that creates a new object. -It may look as follows. - -
+ A WebAssembly build of GAP + running entirely in your browser — useful for trying things out + without installing. Not all packages work, working memory is + capped, and performance is reduced compared to a native build. + For real work, install GAP from + www.gap-system.org. +
++ GAP is a system for + computational discrete algebra, with particular emphasis on + computational group theory. This page is a self-contained + WebAssembly build, served as a static site and run inside a + Web Worker; you interact with it through an + xterm-pty + terminal in the page below. +
+
+ To get started, try 1+1;,
+ Factorial(20);, or SymmetricGroup(5);.
+ The full GAP
+ manuals apply, with two caveats: some packages won't load
+ (anything that needs a native compiler or system library), and
+ anything that wants the local filesystem won't work.
+
+ Files downloaded on first visit are cached in your browser's + IndexedDB, so subsequent visits start much faster. Clear the + site data to reset the cache. +
++ GAP is free software, distributed under the + GNU General Public License (version 2 or + later). See the copyright notice for + the full statement. +
+SharedArrayBuffer, which is only
+ available when the page is served with the headers
+ Cross-Origin-Opener-Policy: same-origin and
+ Cross-Origin-Embedder-Policy: require-corp. The
+ bundled service worker handles this on hosts where you can't set
+ headers (e.g. GitHub Pages); for local hosting use
+ etc/emscripten/serve.py.
+