| Abstract: | In this thesis we will give an interesting relation between finite rings and their
graphs, such relations are obtained in following way.
Consider a directed graph              	
  
    on a finite ring
        
    , where 	
   are sets of vertices and edges respectively, and                 
   defined by
   
            
    . Since   is finite, it has an integer characteristic
        
     . If   is not a prime, then   has zero divisors and      is not a unique
factorization ring, but if it is prime, then   nevertheless could have zero-divisors
(e.g.,
       ). Let   and   be relatively prime numbers, such that
      ,   !   and
define two maps
 "       #,
          $
by  "        
 %&
   and           
 %&
   respectively, so  " and    are homomorphism
maps, suppose that
'()   *+,-. / + is a directed cycle of length . in a
directed graph  , then many interesting algebraic relations will exist between longest
cycles in
  ,
 # and
 $, which will be shown up in the chapter III. |