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MA415 HOMEWORK #5
Due Monday, March 27

  1. Section 5.5, #1, 3, 11, 14, 16.
  2. Section 6.1, #4, 6, 14.
  3. Redefine the ``product'' of two matrices A and B as C=AB, where

    displaymath18

    Let W be the matrix of edges weights for a simple graph; i.e., tex2html_wrap_inline28 equals the weight of edge ij. We define tex2html_wrap_inline32 for tex2html_wrap_inline34 and tex2html_wrap_inline36 if ij is not an edge. Assume tex2html_wrap_inline40 for all i,j. Prove by induction on n that entry i,j of tex2html_wrap_inline48 equals the weight of a minimum weight path from i to j that uses no more than n edges, where the power tex2html_wrap_inline48 is computed according to the new matrix product rule. Then use this to prove that when tex2html_wrap_inline58 , the i,j entry of tex2html_wrap_inline48 equals the weight of the minimum weight path from i to j. Finally, by repeated squaring, use this method to solve Problem 9 in Section 6.1.





Carl Lee
Mon Mar 20 13:59:40 EST 2000