TAILIEUCHUNG - Báo cáo toán học: "Permanents of Hessenberg (0,1)-matrices"

Tuyển tập các báo cáo nghiên cứu khoa học về toán học trên tạp chí toán học quốc tế đề tài: Permanents of Hessenberg (0,1)-matrices. | Permanents of Hessenberg 0 1 -matrices . Olesky Department of Computer Science University of Victoria Victoria BC V8W 3P6 Canada dolesky@ Bryan Shader Department of Mathematics University of Wyoming Laramie WY 82071 bshader@ P. van den Driessche Department of Mathematics University of Victoria Victoria BC V8W 3P4 Canada pvdd@ Submitted Apr 22 2005 Accepted Dec 6 2005 Published Dec 13 2005 Mathematics Subject Classifications 05C50 Abstract Let P m n denote the maximum permanent of an n-by-n lower Hessenberg 0 1 -matrix with m entries equal to 1. A staircased structure for some matrices achieving this maximum is obtained and recursive formulas for computing P m n are given. This structure and results about permanents are used to determine the exact values of P m n for n m 8n 3 and for all nnz Hn nnz H n 2j m nnz Hn where nnz Hn n2 3n 2 2 is the maximum number of ones in an n-by-n Hessenberg 0 1 -matrix. 1 Introduction A transversal of an n-by-n 0 1 -matrix A aij is a collection of n entries of A equal to 1 no two of which are in the same row or column. The permanent of A denoted per A is the number of distinct transversals of A. Equivalently per A 2 aia i a2ơ 2 a n ơ THE ELECTRONIC JOURNAL OF COMBINATORICS 12 2005 R70 1 where the sum is over all permutations Ơ of 1 2 . n . We refer the reader to M for classic results and to CW for a survey of recent research on permanents. A matrix A is a lower Hessenberg matrix if aj 0 whenever j i 2. Throughout the remainder of the paper we abbreviate lower Hessenberg to Hessenberg. Let H m n denote the set of n-by-n Hessenberg 0 1 -matrices with m entries equal to 1 and let P m n denote the maximum permanent of a matrix in H m n . In BR Ch. 7 computation of the permanent of an arbitrary rectangular matrix is considered. Additionally upper and lower bounds for the permanent of such a 0 1 -matrix A are given in terms of the number of ones in each row of A the number of ones in each column of A or the

TÀI LIỆU LIÊN QUAN
TỪ KHÓA LIÊN QUAN
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.