Existentially bound-word subgroup: Difference between revisions

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(New page: {{wikilocal}} {{subgroup property}} ==Definition== Let <math>C</math> be a collection of pairs <math>(w,l)</math> where <math>w</math> is a word and <math>l</math> is a letter used in <m...)
 
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==Definition==
==Definition==


Let <math>C</math> be a collection of pairs <math>(w,l)</math> where <math>w</math> is a word and <math>l</math> is a letter used in <math>w</math>. An element <math>g \in G</math> is said to satisfy the pair <math>(w,l)</math> if we can find values for the other letters of <math>w</math>, with <math>l = g</math>, so that the word <math>w</math> simplifies to the identity element.
An ''existentially quantified word-letter pair'' a pair <math>(w,l)</math> where <math>w</math> is a word and <math>l</math> is a letter used in <math>w</math>. An element <math>g \in G</math> is said to satisfy the pair <math>(w,l)</math> if we can find values for the other letters of <math>w</math>, with <math>l = g</math>, so that the word <math>w</math> simplifies to the identity element. The subgroup corresponding to such a pair is the subgroup generated by all <math>g \in G</math> satisfying the pair.


Then, the existentially bound-word subgroup corresponding to <math>C</math> is defined as the subgroup generated by all elements satisfying at least one <math>(w,l) \in C</math>.
An '''existentially bound-word subgroup''' of a group is a subgroup obtained from subgroups corresponding to existentially quantified word-letter pairs.
 
A subgroup of a group is termed an '''existentially bound-word subgroup''' if there exists a collection <math>C</math> for which it is the corresponding existentially bound-word subgroup.


==Relation with other properties==
==Relation with other properties==

Revision as of 21:54, 2 December 2008

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This article defines a subgroup property: a property that can be evaluated to true/false given a group and a subgroup thereof, invariant under subgroup equivalence. View a complete list of subgroup properties[SHOW MORE]

Definition

An existentially quantified word-letter pair a pair (w,l) where w is a word and l is a letter used in w. An element gG is said to satisfy the pair (w,l) if we can find values for the other letters of w, with l=g, so that the word w simplifies to the identity element. The subgroup corresponding to such a pair is the subgroup generated by all gG satisfying the pair.

An existentially bound-word subgroup of a group is a subgroup obtained from subgroups corresponding to existentially quantified word-letter pairs.

Relation with other properties

Stronger properties

Weaker properties