QR Archives - Quantum Calculus

McKean’s Themes

By oliverknill August 18, 2024 August 18, 2024

Last week, when looking up Henry McKean, I saw that he passed away on April 20, 2024. I don’t recall having met him in person but I have seen some of his work and met some of this students. Eugene Trubowitz was my Analysis 3 (complex analysis) and Analysis 4 …

QR, QR dynamics, simplicial complex

Dark Matter Lemma

By oliverknill August 11, 2024 August 12, 2024

A real symmetric matrix is called a Dirac matrix, if it is a block Jacobi matrix in which the side diagonal entries are nilpotent, meaning . For such a matrix, the square is called the Laplacian. It is block diagonal . If is a continuous function such that is invertible, …