Improving problem solving by exploiting the concept of symmetry
  We investigate the concept of symmetry and its role in problem solving. This paper first defines precisely the elements that constitute a "problem" and its "solution," and gives several examples to illustrate these definitions. Given precise definitions of problems, it is relatively straightforward to construct a search process for finding solutions. Finally this paper attempts to exploit the concept of symmetry in improving problem solving. 
M. A. El-Dosuky, M. Z. Rashad, T. T. Hamza and A.H. EL-Bassiouny
cs.AI