Customizable triangular factorizations of matrices find their applications in computer graphics and lossless transform coding. In this paper, we prove that any N ×N nonsingular matrix A can be factorized into 3 triangular matrices, A = PLUS, where P is a permutation matrix, L is a unit lower triangular matrix, U is an upper triangular matrix of which the diagonal entries are customizable and ca...

is a Hessenberg matrix and its determinant is F2n+2. Furthermore, a Hessenberg matrix is said to be a Fibonacci-Hessenberg matrix [2] if its determinant is in the form tFn−1 + Fn−2 or Fn−1 + tFn−2 for some real or complex number t. In [1] several types of Hessenberg matrices whose determinants are Fibonacci numbers were calculated by using the basic definition of the determinant as a signed sum...

We study a natural random walk over the upper triangular matrices, with entries in the field Z2, generated by steps which add row i + 1 to row i. We show that the mixing time of the lazy random walk is O(n) which is optimal up to constants. Our proof makes key use of the linear structure of the group and extends to walks on the upper triangular matrices over the fields Zq for q prime.

The singular value decomposition (SVD) of a 2-by-2 complex matrix does not occur as frequently as that of a 2-by-2 real upper triangular matrix. The commonly used QR method for SVD consists of two stages. In the first stage, a matrix is reduced to bidiagonal form using, say, Householder transformations on both sides. In the second stage, the bidiagonal matrix resulted from the first stage is di...