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A group is a set of objects, sometimes referred to as <math>G \ </math>, and a rule of composition, <math>* \ </math>, such that
 
A group is a set of objects, sometimes referred to as <math>G \ </math>, and a rule of composition, <math>* \ </math>, such that
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#. There is an element of <math>G \ </math>, call it <math>e \ </math>, such that for any <math>x \ </math> in <math>G \ </math>, <math>e*x = x*e = x \ </math>.  This element is called the identity of the group.  We write <math>x \in G \ </math> to mean that <math>x \ </math> is in <math>G \ </math>.
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#There is an element of <math>G \ </math>, call it <math>e \ </math>, such that for any <math>x \ </math> in <math>G \ </math>, <math>e*x = x*e = x \ </math>.  This element is called the identity of the group.  We write <math>x \in G \ </math> to mean that <math>x \ </math> is in <math>G \ </math>.
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#For any two <math>x, y \in G \ </math>, their composition <math>x*y \in G \ </math>.
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#. For any two <math>x, y \in G \ </math>, their composition <math>x*y \in G \ </math>.
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#For any three <math>x,y,z \in G, x*(y*z) = (x*y)*z \ </math>
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#. For any three <math>x,y,z \in G, x*(y*z) = (x*y)*z \ </math>
      
[[Category:Algebra Terms]]
 
[[Category:Algebra Terms]]
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