The Main Diagonal of a Permutation Matrix
نویسندگان
چکیده
By counting 1’s in the “right half” of 2w consecutive rows, we locate the main diagonal of any doubly infinite permutation matrix with bandwidth w. Then the matrix can be correctly centered and factored into blockdiagonal permutation matrices. Part II of the paper discusses the same questions for the much larger class of band-dominated matrices. The main diagonal is determined by the Fredholm index of a singly infinite submatrix. Thus the main diagonal is determined “at infinity” in general, but from only 2w rows for banded permutations. Mathematics subject classification (2010): 15A23; 47A53, 47B36.
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