semigroups: Anything that associates
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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| Versions [RSS] | 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, 0.18.3, 0.18.4, 0.18.5, 0.19, 0.19.1, 0.19.2, 0.20 |
|---|---|
| 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 && <0.3) [details] |
| License | BSD-3-Clause |
| Copyright | Copyright (C) 2011-2013 Edward A. Kmett |
| Author | Edward A. Kmett |
| Maintainer | Edward A. Kmett <ekmett@gmail.com> |
| Category | Algebra, Data, Data Structures, Math |
| Home page | http://github.com/ekmett/semigroups/ |
| Bug tracker | http://github.com/ekmett/semigroups/issues |
| Source repo | head: git clone git://github.com/ekmett/semigroups.git |
| Uploaded | by EdwardKmett at 2014-01-14T22:20:06Z |
| Distributions | Debian:0.19.1, Fedora:0.20, FreeBSD:0.16.2.2, LTSHaskell:0.20, NixOS:0.20, Stackage:0.20, openSUSE:0.20 |
| Reverse Dependencies | 907 direct, 13952 indirect [details] |
| Downloads | 487305 total (506 in the last 30 days) |
| Rating | 2.75 (votes: 9) [estimated by Bayesian average] |
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| Status | Docs available [build log] Successful builds reported [all 1 reports] |
Readme for semigroups-0.12.2
[back to package description]semigroups
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