Difference between revisions of "Free monoid generated by"

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** {{M|1=e=()}} - the "empty" tuple.
 
** {{M|1=e=()}} - the "empty" tuple.
 
The proof that this is indeed a monoid is below
 
The proof that this is indeed a monoid is below
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==Terminology==
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The finite [[tuple|tuples]] of {{M|F}} are sometimes called "words". {{Warning|The "word" terminology may be specific to the [[free group]], however I wouldn't be surprised if word is used in this context too, so I deem it still worth mentioning}}
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{{Requires references|grade=D|msg=While not explicitly said, the main reference doesn't deal with these objects in great detail, however usually such tuples are called words, at least with free groups (see warning)}}
 
==Examples==
 
==Examples==
 
* This page can be considered an element of the monoid generated by the alphabet ([[union]] all the symbols too)
 
* This page can be considered an element of the monoid generated by the alphabet ([[union]] all the symbols too)

Revision as of 14:00, 20 July 2016

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Be sure to check Discussion of the free monoid and free semigroup generated by a set, as there are some things to note

Definition

Given a set, X, there is a free monoid, (F,)[1].

  • The elements of F are all the finite tuples, (x1,,xn) (where xiX)
  • The monoid operation (:F×FF) is concatenation:
    • :((x1,,xn),(y1,,yn))(x1,,xn,y1,,yn)
  • The identity element of the monoid is:
    • e=() - the "empty" tuple.

The proof that this is indeed a monoid is below

Terminology

The finite tuples of F are sometimes called "words". Warning:The "word" terminology may be specific to the free group, however I wouldn't be surprised if word is used in this context too, so I deem it still worth mentioning

Grade: D
This page requires references, it is on a to-do list for being expanded with them.
Please note that this does not mean the content is unreliable, it just means that the author of the page doesn't have a book to hand, or remember the book to find it, which would have been a suitable reference.
The message provided is:
While not explicitly said, the main reference doesn't deal with these objects in great detail, however usually such tuples are called words, at least with free groups (see warning)

Examples

  • This page can be considered an element of the monoid generated by the alphabet (union all the symbols too)

Proof that this is indeed a monoid

  1. Associativity is trivial
  2. Identity element being an identity element is trivial

(These might be good "low hanging fruit" for any newcomers)

References

  1. Jump up Abstract Algebra - Pierre Antoine Grillet

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