Algorithms and Data Structures for an Expanded Family of Matroid Intersection Problems

نویسندگان

  • Greg N. Frederickson
  • Mandayam A. Srinivas
چکیده

Consider a matroid of rank. n in which each element has a real-valued cost and one of d > I colors. A class of matroid intersection problems is studied in which one of the matroids is a partition matroid that specifies that a base have qj elements of color j. for j = I, 2•...• d. Relationships are characterized among the solutions to the family of problems generated when the vector (q l' q2' ... , qd) is allowed to range over all values that sum to n. A fast algorithm is given for solving such matroid intersection problems when d is small. A characterization is presented for how the solution changes when one element changes in cost. Data structures are given for updating the solution on-line each time the cost of an arbitrary matroid element is modified. Efficient update algorithms are given for maintaining a color-constrained minimum spanning tree in either a general or a planar graph. An application of the techniques to finding a minimum spanning tree with several degree-constrained vertices is described.

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عنوان ژورنال:
  • SIAM J. Comput.

دوره 18  شماره 

صفحات  -

تاریخ انتشار 1989