Free monoid generated by

From Maths
Revision as of 13:57, 20 July 2016 by Alec (Talk | contribs) (Created page with "{{Stub page|grade=A|msg=Demote once fleshed out and minimally complete}} ==Definition== Given a set, {{M|X}}, there is a ''free'' monoid, {{M|(F,*)}}{{rAAPAG}}. * The...")

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search
Stub grade: A
This page is a stub
This page is a stub, so it contains little or minimal information and is on a to-do list for being expanded.The message provided is:
Demote once fleshed out and minimally complete

Definition

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

  • The elements of [ilmath]F[/ilmath] are all the finite tuples, [ilmath](x_1,\ldots,x_n)[/ilmath] (where [ilmath]x_i\in X[/ilmath])
  • The monoid operation ([ilmath]*:F\times F\rightarrow F[/ilmath]) is concatenation:
    • [ilmath]*:((x_1,\ldots,x_n),(y_1,\ldots,y_n))\mapsto(x_1,\ldots,x_n,y_1,\ldots,y_n)[/ilmath]
  • The identity element of the monoid is:
    • [ilmath]e=()[/ilmath] - the "empty" tuple.

The proof that this is indeed a monoid is below

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. Abstract Algebra - Pierre Antoine Grillet

Template:Monoid navbox