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The 5th roots of unity in the complex plane form a group under multiplication. Each non-identity element generates the group. In abstract algebra, a generating set of a group is a subset of the group set such that every element of the group can be expressed as a combination (under the group operation) of finitely many elements of the subset and their inverses.
Informally, G has the above presentation if it is the "freest group" generated by S subject only to the relations R. Formally, the group G is said to have the above presentation if it is isomorphic to the quotient of a free group on S by the normal subgroup generated by the relations R. As a simple example, the cyclic group of order n has the ...
It is commonly the case that the generating set has a simpler set of properties than the generated set, thus making it easier to discuss and examine. It is usually the case that properties of the generating set are in some way preserved by the act of generation; likewise, the properties of the generated set are often reflected in the generating ...
The free abelian group on S can be explicitly identified as the free group F(S) modulo the subgroup generated by its commutators, [F(S), F(S)], i.e. its abelianisation. In other words, the free abelian group on S is the set of words that are distinguished only up to the order of letters. The rank of a free group can therefore also be defined as ...
A free group has a unique normal form i.e. each element in is represented by a unique reduced word. Proof. An elementary transformation of a word w ∈ G {\displaystyle w\in G} consists of inserting or deleting a part of the form a a − 1 {\displaystyle aa^{-1}} with a ∈ S ± {\displaystyle a\in S^{\pm }} .
The manipulations of the Rubik's Cube form the Rubik's Cube group.. In mathematics, a group is a set with an operation that associates an element of the set to every pair of elements of the set (as does every binary operation) and satisfies the following constraints: the operation is associative, it has an identity element, and every element of the set has an inverse element.
This can be extended to a complete classification of all finitely generated abelian groups, that is all abelian groups that are generated by a finite set. The situation is much more complicated for the non-abelian groups. Free group. Given any set A, one can define a group as the smallest group containing the free semigroup of A.
For, if is finitely generated by a set , it is a quotient of the free abelian group over by a free abelian subgroup, the subgroup generated by the relators of the presentation of . But since this subgroup is itself free abelian, it is also finitely generated, and its basis (together with the commutators over B {\displaystyle B} ) forms a finite ...