190 citations · 210 across the 8 of their papers we have counts for
5 papers · 1 filter
The Pseudoinverse of is (?)
Michał P. Karpowicz, Gilbert Strang
This paper gives three formulas for the pseudoinverse of a matrix product . The first is sometimes correct, the second is always correct, and the third is almost never corr…
Elimination and Factorization
Gilbert Strang
If a matrix has rank , then its row echelon form (from elimination) contains the identity matrix in its first independent columns. How do we \emph{interpret the matrix}…
A Local Inverse Formula and a Factorization
Gilbert Strang, Shev MacNamara
When a matrix has a banded inverse there is a remarkable formula that quickly computes that inverse, using only local information in the original matrix. This local inverse formula…
The Main Diagonal of a Permutation Matrix
Marko Lindner, Gilbert Strang
By counting 1's in the "right half" of consecutive rows, we locate the main diagonal of any doubly infinite permutation matrix with bandwidth . Then the matrix can be corre…
Wavelet transforms versus Fourier transforms
Gilbert Strang
This note is a very basic introduction to wavelets. It starts with an orthogonal basis of piecewise constant functions, constructed by dilation and translation. The ``wavelet trans…