The semigroups package

[Tags:bsd3, library]

In mathematics, a semigroup is an algebraic structure consisting of a set together with an associative binary operation. A semigroup generalizes a monoid in that there might not exist an identity element. It also (originally) generalized a group (a monoid with all inverses) to a type where every element did not have to have an inverse, thus the name semigroup.


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Properties

Versions 0.1.0, 0.2.0, 0.3.0, 0.3.1, 0.3.2, 0.3.3, 0.3.4, 0.3.4.1, 0.3.4.2, 0.4.0, 0.5.0, 0.5.0.1, 0.5.0.2, 0.6, 0.6.1, 0.7.0, 0.7.1, 0.7.1.1, 0.7.1.2, 0.8, 0.8.0.1, 0.8.2, 0.8.3, 0.8.3.1, 0.8.3.2, 0.8.4, 0.8.4.1, 0.8.5, 0.9, 0.9.1, 0.9.2, 0.10, 0.11, 0.12, 0.12.0.1, 0.12.1, 0.12.2, 0.13, 0.13.0.1, 0.14, 0.15, 0.15.1, 0.15.2, 0.15.3, 0.15.4, 0.16, 0.16.0.1, 0.16.1, 0.16.2, 0.16.2.1, 0.16.2.2, 0.17, 0.17.0.1, 0.18, 0.18.0.1, 0.18.1, 0.18.2
Dependencies base (>=2 && <5), bytestring (>=0.9 && <1), containers (>=0.3 && <0.6), hashable (>=1.1 && <1.3), nats (>=0.1 && <1), text (>=0.10 && <2), unordered-containers (==0.2.*) [details]
License BSD3
Copyright Copyright (C) 2011-2013 Edward A. Kmett
Author Edward A. Kmett
Maintainer Edward A. Kmett <ekmett@gmail.com>
Stability provisional
Category Algebra, Data, Data Structures, Math
Home page http://github.com/ekmett/semigroups/
Bug tracker http://github.com/ekmett/semigroups/issues
Source repository head: git clone git://github.com/ekmett/semigroups.git
Uploaded Tue Jan 14 22:20:06 UTC 2014 by EdwardKmett
Distributions Arch:0.18.2, Debian:0.18.0.1, Fedora:0.16.0.1, FreeBSD:0.16.2.2, LTSHaskell:0.18.1, NixOS:0.18.2, Stackage:0.18.2
Downloads 233333 total (170 in the last 30 days)
Votes
4 []
Status Docs available [build log]
Successful builds reported [all 1 reports]

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base2DisabledAutomatic

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Maintainer's Corner

For package maintainers and hackage trustees

Readme for semigroups

Readme for semigroups-0.12.2

semigroups

Build Status

Haskellers are usually familiar with monoids. A monoid has an appending operation <> or mappend and an identity element mempty. A Semigroup has an append <>, but does not require an mempty element. A Monoid can be made a Semigroup with just instance Semigroup MyMonoid

More formally, a semigroup is an algebraic structure consisting of a set together with an associative binary operation. A semigroup generalizes a monoid in that there might not exist an identity element. It also (originally) generalized a group (a monoid with all inverses) to a type where every element did not have to have an inverse, thus the name semigroup.

Semigroups appear all over the place, except in the Haskell Prelude, so they are packaged here.

Contact Information

Contributions and bug reports are welcome!

Please feel free to contact me through github or on the #haskell IRC channel on irc.freenode.net.

-Edward Kmett