Simplifying matrix differential equations with general coefficients

Autor: Tsui, Man Cheung
Rok vydání: 2022
Předmět:
Druh dokumentu: Working Paper
Popis: We show that the $n\times n$ matrix differential equation $\delta(Y)=AY$ with $n^2$ general coefficients cannot be simplified to an equation in less than $n$ parameters by using gauge transformations whose coefficients are rational functions in the matrix entries of $A$ and their derivatives. Our proof uses differential Galois theory and a differential analogue of essential dimension. We also bound the minimum number of parameters needed to describe some generic Picard-Vessiot extensions.
Comment: 13 pages. Corrected miscitation of [1] on page 5; added Example 2.2; small grammatical change
Databáze: arXiv